From 52369882d8209ef5b7a0c7baf6ab474d7783fa8c Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Tue, 19 Sep 2023 11:49:12 -0700
Subject: [PATCH] [promises] Add tracing to seq, join variants (#34401)

Co-authored-by: ctiller <ctiller@users.noreply.github.com>
---
 CMakeLists.txt                           |  18 +
 build_autogenerated.yaml                 |  34 ++
 src/core/BUILD                           |   4 +
 src/core/lib/promise/detail/join_state.h | 486 +++++++++++++++++++++++
 src/core/lib/promise/detail/seq_state.h  | 418 +++++++++++++++++++
 test/core/promise/seq_test.cc            |   1 +
 tools/codegen/core/gen_join.py           |  11 +
 tools/codegen/core/gen_seq.py            |  16 +-
 8 files changed, 987 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 32b41e65245..ef322870677 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5549,7 +5549,9 @@ endif()
 if(gRPC_BUILD_TESTS)
 
 add_executable(activity_test
+  src/core/lib/debug/trace.cc
   src/core/lib/promise/activity.cc
+  src/core/lib/promise/trace.cc
   test/core/promise/activity_test.cc
 )
 target_compile_features(activity_test PUBLIC cxx_std_14)
@@ -8762,6 +8764,7 @@ add_executable(chunked_vector_test
   src/core/lib/iomgr/executor.cc
   src/core/lib/iomgr/iomgr_internal.cc
   src/core/lib/promise/activity.cc
+  src/core/lib/promise/trace.cc
   src/core/lib/resource_quota/arena.cc
   src/core/lib/resource_quota/memory_quota.cc
   src/core/lib/resource_quota/periodic_update.cc
@@ -11866,6 +11869,7 @@ add_executable(flow_control_test
   src/core/lib/iomgr/executor.cc
   src/core/lib/iomgr/iomgr_internal.cc
   src/core/lib/promise/activity.cc
+  src/core/lib/promise/trace.cc
   src/core/lib/resource_quota/memory_quota.cc
   src/core/lib/resource_quota/periodic_update.cc
   src/core/lib/resource_quota/resource_quota.cc
@@ -14486,7 +14490,9 @@ endif()
 if(gRPC_BUILD_TESTS)
 
 add_executable(inter_activity_pipe_test
+  src/core/lib/debug/trace.cc
   src/core/lib/promise/activity.cc
+  src/core/lib/promise/trace.cc
   test/core/promise/inter_activity_pipe_test.cc
 )
 target_compile_features(inter_activity_pipe_test PUBLIC cxx_std_14)
@@ -14837,6 +14843,8 @@ endif()
 if(gRPC_BUILD_TESTS)
 
 add_executable(join_test
+  src/core/lib/debug/trace.cc
+  src/core/lib/promise/trace.cc
   test/core/promise/join_test.cc
 )
 target_compile_features(join_test PUBLIC cxx_std_14)
@@ -14863,6 +14871,7 @@ target_link_libraries(join_test
   ${_gRPC_ALLTARGETS_LIBRARIES}
   gtest
   absl::type_traits
+  absl::statusor
   gpr
 )
 
@@ -15393,6 +15402,8 @@ endif()
 if(gRPC_BUILD_TESTS)
 
 add_executable(loop_test
+  src/core/lib/debug/trace.cc
+  src/core/lib/promise/trace.cc
   test/core/promise/loop_test.cc
 )
 target_compile_features(loop_test PUBLIC cxx_std_14)
@@ -20884,6 +20895,8 @@ endif()
 if(gRPC_BUILD_TESTS)
 
 add_executable(seq_test
+  src/core/lib/debug/trace.cc
+  src/core/lib/promise/trace.cc
   test/core/promise/seq_test.cc
 )
 target_compile_features(seq_test PUBLIC cxx_std_14)
@@ -20910,6 +20923,7 @@ target_link_libraries(seq_test
   ${_gRPC_ALLTARGETS_LIBRARIES}
   gtest
   absl::type_traits
+  absl::statusor
   gpr
 )
 
@@ -25168,6 +25182,8 @@ endif()
 if(gRPC_BUILD_TESTS)
 
 add_executable(try_join_test
+  src/core/lib/debug/trace.cc
+  src/core/lib/promise/trace.cc
   test/core/promise/try_join_test.cc
 )
 target_compile_features(try_join_test PUBLIC cxx_std_14)
@@ -25237,6 +25253,8 @@ endif()
 if(gRPC_BUILD_TESTS)
 
 add_executable(try_seq_test
+  src/core/lib/debug/trace.cc
+  src/core/lib/promise/trace.cc
   test/core/promise/try_seq_test.cc
 )
 target_compile_features(try_seq_test PUBLIC cxx_std_14)
diff --git a/build_autogenerated.yaml b/build_autogenerated.yaml
index a709fed35d6..de1b24c5e55 100644
--- a/build_autogenerated.yaml
+++ b/build_autogenerated.yaml
@@ -4842,6 +4842,7 @@ targets:
   run: false
   language: c++
   headers:
+  - src/core/lib/debug/trace.h
   - src/core/lib/gprpp/atomic_utils.h
   - src/core/lib/gprpp/bitset.h
   - src/core/lib/gprpp/orphanable.h
@@ -4860,10 +4861,13 @@ targets:
   - src/core/lib/promise/poll.h
   - src/core/lib/promise/promise.h
   - src/core/lib/promise/seq.h
+  - src/core/lib/promise/trace.h
   - src/core/lib/promise/wait_set.h
   - test/core/promise/test_wakeup_schedulers.h
   src:
+  - src/core/lib/debug/trace.cc
   - src/core/lib/promise/activity.cc
+  - src/core/lib/promise/trace.cc
   - test/core/promise/activity_test.cc
   deps:
   - gtest
@@ -6746,6 +6750,7 @@ targets:
   - src/core/lib/promise/poll.h
   - src/core/lib/promise/race.h
   - src/core/lib/promise/seq.h
+  - src/core/lib/promise/trace.h
   - src/core/lib/resource_quota/arena.h
   - src/core/lib/resource_quota/memory_quota.h
   - src/core/lib/resource_quota/periodic_update.h
@@ -6786,6 +6791,7 @@ targets:
   - src/core/lib/iomgr/executor.cc
   - src/core/lib/iomgr/iomgr_internal.cc
   - src/core/lib/promise/activity.cc
+  - src/core/lib/promise/trace.cc
   - src/core/lib/resource_quota/arena.cc
   - src/core/lib/resource_quota/memory_quota.cc
   - src/core/lib/resource_quota/periodic_update.cc
@@ -8537,6 +8543,7 @@ targets:
   - src/core/lib/promise/poll.h
   - src/core/lib/promise/race.h
   - src/core/lib/promise/seq.h
+  - src/core/lib/promise/trace.h
   - src/core/lib/resource_quota/memory_quota.h
   - src/core/lib/resource_quota/periodic_update.h
   - src/core/lib/resource_quota/resource_quota.h
@@ -8581,6 +8588,7 @@ targets:
   - src/core/lib/iomgr/executor.cc
   - src/core/lib/iomgr/iomgr_internal.cc
   - src/core/lib/promise/activity.cc
+  - src/core/lib/promise/trace.cc
   - src/core/lib/resource_quota/memory_quota.cc
   - src/core/lib/resource_quota/periodic_update.cc
   - src/core/lib/resource_quota/resource_quota.cc
@@ -9987,6 +9995,7 @@ targets:
   build: test
   language: c++
   headers:
+  - src/core/lib/debug/trace.h
   - src/core/lib/gprpp/atomic_utils.h
   - src/core/lib/gprpp/orphanable.h
   - src/core/lib/gprpp/ref_counted.h
@@ -10001,9 +10010,12 @@ targets:
   - src/core/lib/promise/inter_activity_pipe.h
   - src/core/lib/promise/poll.h
   - src/core/lib/promise/seq.h
+  - src/core/lib/promise/trace.h
   - test/core/promise/test_wakeup_schedulers.h
   src:
+  - src/core/lib/debug/trace.cc
   - src/core/lib/promise/activity.cc
+  - src/core/lib/promise/trace.cc
   - test/core/promise/inter_activity_pipe_test.cc
   deps:
   - gtest
@@ -10245,17 +10257,22 @@ targets:
   build: test
   language: c++
   headers:
+  - src/core/lib/debug/trace.h
   - src/core/lib/gprpp/bitset.h
   - src/core/lib/promise/detail/join_state.h
   - src/core/lib/promise/detail/promise_like.h
   - src/core/lib/promise/join.h
   - src/core/lib/promise/map.h
   - src/core/lib/promise/poll.h
+  - src/core/lib/promise/trace.h
   src:
+  - src/core/lib/debug/trace.cc
+  - src/core/lib/promise/trace.cc
   - test/core/promise/join_test.cc
   deps:
   - gtest
   - absl/meta:type_traits
+  - absl/status:statusor
   - gpr
   uses_polling: false
 - name: json_object_loader_test
@@ -10556,6 +10573,7 @@ targets:
   build: test
   language: c++
   headers:
+  - src/core/lib/debug/trace.h
   - src/core/lib/promise/detail/basic_seq.h
   - src/core/lib/promise/detail/promise_factory.h
   - src/core/lib/promise/detail/promise_like.h
@@ -10563,7 +10581,10 @@ targets:
   - src/core/lib/promise/loop.h
   - src/core/lib/promise/poll.h
   - src/core/lib/promise/seq.h
+  - src/core/lib/promise/trace.h
   src:
+  - src/core/lib/debug/trace.cc
+  - src/core/lib/promise/trace.cc
   - test/core/promise/loop_test.cc
   deps:
   - gtest
@@ -14021,17 +14042,22 @@ targets:
   build: test
   language: c++
   headers:
+  - src/core/lib/debug/trace.h
   - src/core/lib/promise/detail/basic_seq.h
   - src/core/lib/promise/detail/promise_factory.h
   - src/core/lib/promise/detail/promise_like.h
   - src/core/lib/promise/detail/seq_state.h
   - src/core/lib/promise/poll.h
   - src/core/lib/promise/seq.h
+  - src/core/lib/promise/trace.h
   src:
+  - src/core/lib/debug/trace.cc
+  - src/core/lib/promise/trace.cc
   - test/core/promise/seq_test.cc
   deps:
   - gtest
   - absl/meta:type_traits
+  - absl/status:statusor
   - gpr
   uses_polling: false
 - name: sequential_connectivity_test
@@ -16678,13 +16704,17 @@ targets:
   build: test
   language: c++
   headers:
+  - src/core/lib/debug/trace.h
   - src/core/lib/gprpp/bitset.h
   - src/core/lib/promise/detail/join_state.h
   - src/core/lib/promise/detail/promise_like.h
   - src/core/lib/promise/map.h
   - src/core/lib/promise/poll.h
+  - src/core/lib/promise/trace.h
   - src/core/lib/promise/try_join.h
   src:
+  - src/core/lib/debug/trace.cc
+  - src/core/lib/promise/trace.cc
   - test/core/promise/try_join_test.cc
   deps:
   - gtest
@@ -16709,14 +16739,18 @@ targets:
   build: test
   language: c++
   headers:
+  - src/core/lib/debug/trace.h
   - src/core/lib/promise/detail/basic_seq.h
   - src/core/lib/promise/detail/promise_factory.h
   - src/core/lib/promise/detail/promise_like.h
   - src/core/lib/promise/detail/seq_state.h
   - src/core/lib/promise/detail/status.h
   - src/core/lib/promise/poll.h
+  - src/core/lib/promise/trace.h
   - src/core/lib/promise/try_seq.h
   src:
+  - src/core/lib/debug/trace.cc
+  - src/core/lib/promise/trace.cc
   - test/core/promise/try_seq_test.cc
   deps:
   - gtest
diff --git a/src/core/BUILD b/src/core/BUILD
index 4e59c1dc97c..c15c37e3c74 100644
--- a/src/core/BUILD
+++ b/src/core/BUILD
@@ -630,8 +630,10 @@ grpc_cc_library(
         "construct_destruct",
         "poll",
         "promise_like",
+        "promise_trace",
         "//:gpr",
         "//:gpr_platform",
+        "//:grpc_trace",
     ],
 )
 
@@ -702,7 +704,9 @@ grpc_cc_library(
         "poll",
         "promise_factory",
         "promise_like",
+        "promise_trace",
         "//:gpr",
+        "//:grpc_trace",
     ],
 )
 
diff --git a/src/core/lib/promise/detail/join_state.h b/src/core/lib/promise/detail/join_state.h
index 369d98302a4..84a3f37188b 100644
--- a/src/core/lib/promise/detail/join_state.h
+++ b/src/core/lib/promise/detail/join_state.h
@@ -25,10 +25,12 @@
 
 #include <grpc/support/log.h>
 
+#include "src/core/lib/debug/trace.h"
 #include "src/core/lib/gprpp/bitset.h"
 #include "src/core/lib/gprpp/construct_destruct.h"
 #include "src/core/lib/promise/detail/promise_like.h"
 #include "src/core/lib/promise/poll.h"
+#include "src/core/lib/promise/trace.h"
 
 namespace grpc_core {
 namespace promise_detail {
@@ -91,7 +93,16 @@ struct JoinState<Traits, P0, P1> {
       typename Traits::template ResultType<std::tuple<Result0, Result1>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/2", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/2 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -101,9 +112,20 @@ struct JoinState<Traits, P0, P1> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/2 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/2", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/2 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -113,6 +135,8 @@ struct JoinState<Traits, P0, P1> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/2 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(std::move(result0), std::move(result1))};
@@ -195,7 +219,16 @@ struct JoinState<Traits, P0, P1, P2> {
       std::tuple<Result0, Result1, Result2>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/3", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/3 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -205,9 +238,20 @@ struct JoinState<Traits, P0, P1, P2> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/3 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/3", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/3 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -217,9 +261,20 @@ struct JoinState<Traits, P0, P1, P2> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/3 already ready", this);
     }
     if (!ready.is_set(2)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 3/3", this);
+      }
       auto poll = promise2();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 3/3 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(2);
@@ -229,6 +284,8 @@ struct JoinState<Traits, P0, P1, P2> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 3/3 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(std::move(result0), std::move(result1),
@@ -330,7 +387,16 @@ struct JoinState<Traits, P0, P1, P2, P3> {
       std::tuple<Result0, Result1, Result2, Result3>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/4", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/4 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -340,9 +406,20 @@ struct JoinState<Traits, P0, P1, P2, P3> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/4 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/4", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/4 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -352,9 +429,20 @@ struct JoinState<Traits, P0, P1, P2, P3> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/4 already ready", this);
     }
     if (!ready.is_set(2)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 3/4", this);
+      }
       auto poll = promise2();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 3/4 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(2);
@@ -364,9 +452,20 @@ struct JoinState<Traits, P0, P1, P2, P3> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 3/4 already ready", this);
     }
     if (!ready.is_set(3)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 4/4", this);
+      }
       auto poll = promise3();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 4/4 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(3);
@@ -376,6 +475,8 @@ struct JoinState<Traits, P0, P1, P2, P3> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 4/4 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(std::move(result0), std::move(result1),
@@ -496,7 +597,16 @@ struct JoinState<Traits, P0, P1, P2, P3, P4> {
       std::tuple<Result0, Result1, Result2, Result3, Result4>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/5", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/5 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -506,9 +616,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/5 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/5", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/5 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -518,9 +639,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/5 already ready", this);
     }
     if (!ready.is_set(2)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 3/5", this);
+      }
       auto poll = promise2();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 3/5 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(2);
@@ -530,9 +662,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 3/5 already ready", this);
     }
     if (!ready.is_set(3)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 4/5", this);
+      }
       auto poll = promise3();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 4/5 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(3);
@@ -542,9 +685,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 4/5 already ready", this);
     }
     if (!ready.is_set(4)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 5/5", this);
+      }
       auto poll = promise4();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 5/5 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(4);
@@ -554,6 +708,8 @@ struct JoinState<Traits, P0, P1, P2, P3, P4> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 5/5 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(std::move(result0), std::move(result1),
@@ -693,7 +849,16 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5> {
       std::tuple<Result0, Result1, Result2, Result3, Result4, Result5>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/6", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/6 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -703,9 +868,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/6 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/6", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/6 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -715,9 +891,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/6 already ready", this);
     }
     if (!ready.is_set(2)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 3/6", this);
+      }
       auto poll = promise2();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 3/6 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(2);
@@ -727,9 +914,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 3/6 already ready", this);
     }
     if (!ready.is_set(3)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 4/6", this);
+      }
       auto poll = promise3();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 4/6 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(3);
@@ -739,9 +937,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 4/6 already ready", this);
     }
     if (!ready.is_set(4)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 5/6", this);
+      }
       auto poll = promise4();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 5/6 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(4);
@@ -751,9 +960,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 5/6 already ready", this);
     }
     if (!ready.is_set(5)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 6/6", this);
+      }
       auto poll = promise5();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 6/6 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(5);
@@ -763,6 +983,8 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 6/6 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(std::move(result0), std::move(result1),
@@ -920,7 +1142,16 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
       Result0, Result1, Result2, Result3, Result4, Result5, Result6>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/7", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/7 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -930,9 +1161,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/7 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/7", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/7 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -942,9 +1184,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/7 already ready", this);
     }
     if (!ready.is_set(2)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 3/7", this);
+      }
       auto poll = promise2();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 3/7 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(2);
@@ -954,9 +1207,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 3/7 already ready", this);
     }
     if (!ready.is_set(3)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 4/7", this);
+      }
       auto poll = promise3();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 4/7 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(3);
@@ -966,9 +1230,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 4/7 already ready", this);
     }
     if (!ready.is_set(4)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 5/7", this);
+      }
       auto poll = promise4();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 5/7 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(4);
@@ -978,9 +1253,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 5/7 already ready", this);
     }
     if (!ready.is_set(5)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 6/7", this);
+      }
       auto poll = promise5();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 6/7 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(5);
@@ -990,9 +1276,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 6/7 already ready", this);
     }
     if (!ready.is_set(6)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 7/7", this);
+      }
       auto poll = promise6();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 7/7 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(6);
@@ -1002,6 +1299,8 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 7/7 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(std::move(result0), std::move(result1),
@@ -1179,7 +1478,16 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
       Result0, Result1, Result2, Result3, Result4, Result5, Result6, Result7>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/8", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -1189,9 +1497,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/8 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/8", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -1201,9 +1520,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/8 already ready", this);
     }
     if (!ready.is_set(2)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 3/8", this);
+      }
       auto poll = promise2();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 3/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(2);
@@ -1213,9 +1543,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 3/8 already ready", this);
     }
     if (!ready.is_set(3)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 4/8", this);
+      }
       auto poll = promise3();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 4/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(3);
@@ -1225,9 +1566,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 4/8 already ready", this);
     }
     if (!ready.is_set(4)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 5/8", this);
+      }
       auto poll = promise4();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 5/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(4);
@@ -1237,9 +1589,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 5/8 already ready", this);
     }
     if (!ready.is_set(5)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 6/8", this);
+      }
       auto poll = promise5();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 6/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(5);
@@ -1249,9 +1612,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 6/8 already ready", this);
     }
     if (!ready.is_set(6)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 7/8", this);
+      }
       auto poll = promise6();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 7/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(6);
@@ -1261,9 +1635,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 7/8 already ready", this);
     }
     if (!ready.is_set(7)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 8/8", this);
+      }
       auto poll = promise7();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 8/8 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(7);
@@ -1273,6 +1658,8 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 8/8 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(std::move(result0), std::move(result1),
@@ -1469,7 +1856,16 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
                  Result7, Result8>>;
   Poll<Result> PollOnce() {
     if (!ready.is_set(0)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 1/9", this);
+      }
       auto poll = promise0();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 1/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(0);
@@ -1479,9 +1875,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 1/9 already ready", this);
     }
     if (!ready.is_set(1)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 2/9", this);
+      }
       auto poll = promise1();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 2/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(1);
@@ -1491,9 +1898,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 2/9 already ready", this);
     }
     if (!ready.is_set(2)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 3/9", this);
+      }
       auto poll = promise2();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 3/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(2);
@@ -1503,9 +1921,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 3/9 already ready", this);
     }
     if (!ready.is_set(3)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 4/9", this);
+      }
       auto poll = promise3();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 4/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(3);
@@ -1515,9 +1944,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 4/9 already ready", this);
     }
     if (!ready.is_set(4)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 5/9", this);
+      }
       auto poll = promise4();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 5/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(4);
@@ -1527,9 +1967,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 5/9 already ready", this);
     }
     if (!ready.is_set(5)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 6/9", this);
+      }
       auto poll = promise5();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 6/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(5);
@@ -1539,9 +1990,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 6/9 already ready", this);
     }
     if (!ready.is_set(6)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 7/9", this);
+      }
       auto poll = promise6();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 7/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(6);
@@ -1551,9 +2013,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 7/9 already ready", this);
     }
     if (!ready.is_set(7)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 8/9", this);
+      }
       auto poll = promise7();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 8/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(7);
@@ -1563,9 +2036,20 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 8/9 already ready", this);
     }
     if (!ready.is_set(8)) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint 9/9", this);
+      }
       auto poll = promise8();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint 9/9 %s", this,
+                p != nullptr ? (Traits::IsOk(*p) ? "ready" : "early-error")
+                             : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(8);
@@ -1575,6 +2059,8 @@ struct JoinState<Traits, P0, P1, P2, P3, P4, P5, P6, P7, P8> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint 9/9 already ready", this);
     }
     if (ready.all()) {
       return Result{std::make_tuple(
diff --git a/src/core/lib/promise/detail/seq_state.h b/src/core/lib/promise/detail/seq_state.h
index c5be81b11f0..5ee32418a53 100644
--- a/src/core/lib/promise/detail/seq_state.h
+++ b/src/core/lib/promise/detail/seq_state.h
@@ -27,10 +27,12 @@
 
 #include <grpc/support/log.h>
 
+#include "src/core/lib/debug/trace.h"
 #include "src/core/lib/gprpp/construct_destruct.h"
 #include "src/core/lib/promise/detail/promise_factory.h"
 #include "src/core/lib/promise/detail/promise_like.h"
 #include "src/core/lib/promise/poll.h"
+#include "src/core/lib/promise/trace.h"
 
 // A sequence under some traits for some set of callables P, Fs.
 // P should be a promise-like object that yields a value.
@@ -137,8 +139,18 @@ struct SeqState<Traits, P, F0> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/2", this);
+        }
         auto result = prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/2 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -154,7 +166,14 @@ struct SeqState<Traits, P, F0> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/2", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 2/2 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -251,8 +270,18 @@ struct SeqState<Traits, P, F0, F1> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/3", this);
+        }
         auto result = prior.prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/3 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -267,8 +296,18 @@ struct SeqState<Traits, P, F0, F1> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/3", this);
+        }
         auto result = prior.current_promise();
         PromiseResult1* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 2/3 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits1::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits1::IsOk(*p)) {
           return PromiseResultTraits1::template ReturnValue<Result>(
@@ -284,7 +323,14 @@ struct SeqState<Traits, P, F0, F1> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState2: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 3/3", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 3/3 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -408,8 +454,18 @@ struct SeqState<Traits, P, F0, F1, F2> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/4", this);
+        }
         auto result = prior.prior.prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/4 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -424,8 +480,18 @@ struct SeqState<Traits, P, F0, F1, F2> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/4", this);
+        }
         auto result = prior.prior.current_promise();
         PromiseResult1* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 2/4 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits1::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits1::IsOk(*p)) {
           return PromiseResultTraits1::template ReturnValue<Result>(
@@ -440,8 +506,18 @@ struct SeqState<Traits, P, F0, F1, F2> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState2: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 3/4", this);
+        }
         auto result = prior.current_promise();
         PromiseResult2* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 3/4 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits2::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits2::IsOk(*p)) {
           return PromiseResultTraits2::template ReturnValue<Result>(
@@ -457,7 +533,14 @@ struct SeqState<Traits, P, F0, F1, F2> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState3: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 4/4", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 4/4 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -608,8 +691,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/5", this);
+        }
         auto result = prior.prior.prior.prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/5 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -624,8 +717,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/5", this);
+        }
         auto result = prior.prior.prior.current_promise();
         PromiseResult1* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 2/5 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits1::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits1::IsOk(*p)) {
           return PromiseResultTraits1::template ReturnValue<Result>(
@@ -640,8 +743,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState2: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 3/5", this);
+        }
         auto result = prior.prior.current_promise();
         PromiseResult2* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 3/5 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits2::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits2::IsOk(*p)) {
           return PromiseResultTraits2::template ReturnValue<Result>(
@@ -656,8 +769,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState3: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 4/5", this);
+        }
         auto result = prior.current_promise();
         PromiseResult3* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 4/5 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits3::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits3::IsOk(*p)) {
           return PromiseResultTraits3::template ReturnValue<Result>(
@@ -673,7 +796,14 @@ struct SeqState<Traits, P, F0, F1, F2, F3> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState4: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 5/5", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 5/5 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -861,8 +991,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/6", this);
+        }
         auto result = prior.prior.prior.prior.prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/6 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -878,8 +1018,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/6", this);
+        }
         auto result = prior.prior.prior.prior.current_promise();
         PromiseResult1* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 2/6 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits1::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits1::IsOk(*p)) {
           return PromiseResultTraits1::template ReturnValue<Result>(
@@ -894,8 +1044,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState2: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 3/6", this);
+        }
         auto result = prior.prior.prior.current_promise();
         PromiseResult2* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 3/6 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits2::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits2::IsOk(*p)) {
           return PromiseResultTraits2::template ReturnValue<Result>(
@@ -910,8 +1070,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState3: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 4/6", this);
+        }
         auto result = prior.prior.current_promise();
         PromiseResult3* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 4/6 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits3::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits3::IsOk(*p)) {
           return PromiseResultTraits3::template ReturnValue<Result>(
@@ -926,8 +1096,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState4: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 5/6", this);
+        }
         auto result = prior.current_promise();
         PromiseResult4* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 5/6 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits4::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits4::IsOk(*p)) {
           return PromiseResultTraits4::template ReturnValue<Result>(
@@ -943,7 +1123,14 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState5: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 6/6", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 6/6 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -1164,8 +1351,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/7", this);
+        }
         auto result = prior.prior.prior.prior.prior.prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/7 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -1181,8 +1378,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/7", this);
+        }
         auto result = prior.prior.prior.prior.prior.current_promise();
         PromiseResult1* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 2/7 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits1::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits1::IsOk(*p)) {
           return PromiseResultTraits1::template ReturnValue<Result>(
@@ -1198,8 +1405,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState2: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 3/7", this);
+        }
         auto result = prior.prior.prior.prior.current_promise();
         PromiseResult2* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 3/7 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits2::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits2::IsOk(*p)) {
           return PromiseResultTraits2::template ReturnValue<Result>(
@@ -1214,8 +1431,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState3: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 4/7", this);
+        }
         auto result = prior.prior.prior.current_promise();
         PromiseResult3* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 4/7 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits3::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits3::IsOk(*p)) {
           return PromiseResultTraits3::template ReturnValue<Result>(
@@ -1230,8 +1457,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState4: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 5/7", this);
+        }
         auto result = prior.prior.current_promise();
         PromiseResult4* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 5/7 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits4::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits4::IsOk(*p)) {
           return PromiseResultTraits4::template ReturnValue<Result>(
@@ -1246,8 +1483,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState5: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 6/7", this);
+        }
         auto result = prior.current_promise();
         PromiseResult5* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 6/7 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits5::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits5::IsOk(*p)) {
           return PromiseResultTraits5::template ReturnValue<Result>(
@@ -1263,7 +1510,14 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState6: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 7/7", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 7/7 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -1517,9 +1771,19 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/8", this);
+        }
         auto result =
             prior.prior.prior.prior.prior.prior.prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/8 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -1536,8 +1800,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/8", this);
+        }
         auto result = prior.prior.prior.prior.prior.prior.current_promise();
         PromiseResult1* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 2/8 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits1::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits1::IsOk(*p)) {
           return PromiseResultTraits1::template ReturnValue<Result>(
@@ -1553,8 +1827,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState2: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 3/8", this);
+        }
         auto result = prior.prior.prior.prior.prior.current_promise();
         PromiseResult2* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 3/8 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits2::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits2::IsOk(*p)) {
           return PromiseResultTraits2::template ReturnValue<Result>(
@@ -1570,8 +1854,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState3: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 4/8", this);
+        }
         auto result = prior.prior.prior.prior.current_promise();
         PromiseResult3* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 4/8 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits3::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits3::IsOk(*p)) {
           return PromiseResultTraits3::template ReturnValue<Result>(
@@ -1586,8 +1880,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState4: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 5/8", this);
+        }
         auto result = prior.prior.prior.current_promise();
         PromiseResult4* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 5/8 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits4::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits4::IsOk(*p)) {
           return PromiseResultTraits4::template ReturnValue<Result>(
@@ -1602,8 +1906,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState5: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 6/8", this);
+        }
         auto result = prior.prior.current_promise();
         PromiseResult5* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 6/8 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits5::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits5::IsOk(*p)) {
           return PromiseResultTraits5::template ReturnValue<Result>(
@@ -1618,8 +1932,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState6: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 7/8", this);
+        }
         auto result = prior.current_promise();
         PromiseResult6* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 7/8 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits6::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits6::IsOk(*p)) {
           return PromiseResultTraits6::template ReturnValue<Result>(
@@ -1635,7 +1959,14 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState7: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 8/8", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 8/8 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -1923,9 +2254,19 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
   Poll<Result> PollOnce() {
     switch (state) {
       case State::kState0: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 1/9", this);
+        }
         auto result =
             prior.prior.prior.prior.prior.prior.prior.prior.current_promise();
         PromiseResult0* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 1/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits0::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits0::IsOk(*p)) {
           return PromiseResultTraits0::template ReturnValue<Result>(
@@ -1943,9 +2284,19 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState1: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 2/9", this);
+        }
         auto result =
             prior.prior.prior.prior.prior.prior.prior.current_promise();
         PromiseResult1* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 2/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits1::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits1::IsOk(*p)) {
           return PromiseResultTraits1::template ReturnValue<Result>(
@@ -1962,8 +2313,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState2: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 3/9", this);
+        }
         auto result = prior.prior.prior.prior.prior.prior.current_promise();
         PromiseResult2* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 3/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits2::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits2::IsOk(*p)) {
           return PromiseResultTraits2::template ReturnValue<Result>(
@@ -1979,8 +2340,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState3: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 4/9", this);
+        }
         auto result = prior.prior.prior.prior.prior.current_promise();
         PromiseResult3* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 4/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits3::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits3::IsOk(*p)) {
           return PromiseResultTraits3::template ReturnValue<Result>(
@@ -1996,8 +2367,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState4: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 5/9", this);
+        }
         auto result = prior.prior.prior.prior.current_promise();
         PromiseResult4* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 5/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits4::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits4::IsOk(*p)) {
           return PromiseResultTraits4::template ReturnValue<Result>(
@@ -2012,8 +2393,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState5: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 6/9", this);
+        }
         auto result = prior.prior.prior.current_promise();
         PromiseResult5* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 6/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits5::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits5::IsOk(*p)) {
           return PromiseResultTraits5::template ReturnValue<Result>(
@@ -2028,8 +2419,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState6: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 7/9", this);
+        }
         auto result = prior.prior.current_promise();
         PromiseResult6* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 7/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits6::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits6::IsOk(*p)) {
           return PromiseResultTraits6::template ReturnValue<Result>(
@@ -2044,8 +2445,18 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
       }
         ABSL_FALLTHROUGH_INTENDED;
       case State::kState7: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 8/9", this);
+        }
         auto result = prior.current_promise();
         PromiseResult7* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(
+              GPR_DEBUG, "seq[%p]: poll step 8/9 gets %s", this,
+              p != nullptr
+                  ? (PromiseResultTraits7::IsOk(*p) ? "ready" : "early-error")
+                  : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits7::IsOk(*p)) {
           return PromiseResultTraits7::template ReturnValue<Result>(
@@ -2061,7 +2472,14 @@ struct SeqState<Traits, P, F0, F1, F2, F3, F4, F5, F6, F7> {
         ABSL_FALLTHROUGH_INTENDED;
       default:
       case State::kState8: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step 9/9", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step 9/9 gets %s", this,
+                  result.ready() ? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
diff --git a/test/core/promise/seq_test.cc b/test/core/promise/seq_test.cc
index 7e5bd9695b8..8bfd4fadbc8 100644
--- a/test/core/promise/seq_test.cc
+++ b/test/core/promise/seq_test.cc
@@ -16,6 +16,7 @@
 
 #include <stdint.h>
 
+#include <algorithm>
 #include <memory>
 #include <string>
 #include <vector>
diff --git a/tools/codegen/core/gen_join.py b/tools/codegen/core/gen_join.py
index ab081e4af8f..cc978eba285 100755
--- a/tools/codegen/core/gen_join.py
+++ b/tools/codegen/core/gen_join.py
@@ -69,7 +69,15 @@ struct JoinState<Traits, ${",".join(f"P{i}" for i in range(0,n))}> {
   Poll<Result> PollOnce() {
 % for i in range(0,n):
     if (!ready.is_set(${i})) {
+      if (grpc_trace_promise_primitives.enabled()) {
+        gpr_log(GPR_DEBUG, "join[%p]: begin poll joint ${i+1}/${n}", this);
+      }
       auto poll = promise${i}();
+      if (grpc_trace_promise_primitives.enabled()) {
+        auto* p = poll.value_if_ready();
+        gpr_log(GPR_DEBUG, "join[%p]: joint ${i+1}/${n} %s", this, 
+                p != nullptr? (Traits::IsOk(*p)? "ready" : "early-error") : "pending");
+      }
       if (auto* p = poll.value_if_ready()) {
         if (Traits::IsOk(*p)) {
           ready.set(${i});
@@ -79,6 +87,8 @@ struct JoinState<Traits, ${",".join(f"P{i}" for i in range(0,n))}> {
           return Traits::template EarlyReturn<Result>(std::move(*p));
         }
       }
+    } else if (grpc_trace_promise_primitives.enabled()) {
+      gpr_log(GPR_DEBUG, "join[%p]: joint ${i+1}/${n} already ready", this);
     }
 % endfor
     if (ready.all()) {
@@ -106,6 +116,7 @@ front_matter = """
 #include <tuple>
 #include <type_traits>
 #include <utility>
+#include "src/core/lib/promise/trace.h"
 
 namespace grpc_core {
 namespace promise_detail {
diff --git a/tools/codegen/core/gen_seq.py b/tools/codegen/core/gen_seq.py
index 555f1202fa0..cfe0f045906 100755
--- a/tools/codegen/core/gen_seq.py
+++ b/tools/codegen/core/gen_seq.py
@@ -139,11 +139,18 @@ tail${i}:
     switch (state) {
 % for i in range(0,n-1):
       case State::kState${i}: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step ${i+1}/${n}", this);
+        }
         auto result = ${"prior."*(n-1-i)}current_promise();
         PromiseResult${i}* p = result.value_if_ready();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step ${i+1}/${n} gets %s", this, 
+                  p != nullptr? (PromiseResultTraits${i}::IsOk(*p)? "ready" : "early-error") : "pending");
+        }
         if (p == nullptr) return Pending{};
         if (!PromiseResultTraits${i}::IsOk(*p)) {
-            return PromiseResultTraits${i}::template ReturnValue<Result>(std::move(*p));
+          return PromiseResultTraits${i}::template ReturnValue<Result>(std::move(*p));
         }
         Destruct(&${"prior."*(n-1-i)}current_promise);
         auto next_promise = PromiseResultTraits${i}::CallFactory(&${"prior."*(n-1-i)}next_factory, std::move(*p));
@@ -155,7 +162,13 @@ tail${i}:
 % endfor
       default:
       case State::kState${n-1}: {
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: begin poll step ${n}/${n}", this);
+        }
         auto result = current_promise();
+        if (grpc_trace_promise_primitives.enabled()) {
+          gpr_log(GPR_DEBUG, "seq[%p]: poll step ${n}/${n} gets %s", this, result.ready()? "ready" : "pending");
+        }
         auto* p = result.value_if_ready();
         if (p == nullptr) return Pending{};
         return Result(std::move(*p));
@@ -185,6 +198,7 @@ front_matter = """
 #include "src/core/lib/promise/detail/promise_factory.h"
 #include "src/core/lib/promise/detail/promise_like.h"
 #include "src/core/lib/promise/poll.h"
+#include "src/core/lib/promise/trace.h"
 
 // A sequence under some traits for some set of callables P, Fs.
 // P should be a promise-like object that yields a value.