Remove `work_serializer_clears_time_cache` experiment (#37851)

This was put in as a temporary kludge to carry us until `work_serializer_dispatch` was ready, however since #37637 this is a no-op for all known use cases (and I think it's time for `work_serializer_dispatch` to stick).

Closes #37851

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/37851 from ctiller:tc 8ae59415bd
PiperOrigin-RevId: 683255110

bazel/experiments.bzl

@@ -38,7 +38,6 @@ EXPERIMENT_ENABLES = {
     "time_caching_in_party": "time_caching_in_party",
     "trace_record_callops": "trace_record_callops",
     "unconstrained_max_quota_buffer_size": "unconstrained_max_quota_buffer_size",
-    "work_serializer_clears_time_cache": "work_serializer_clears_time_cache",
     "work_serializer_dispatch": "work_serializer_dispatch",
 }
 

src/core/lib/experiments/experiments.cc

@@ -94,10 +94,6 @@ const char* const description_unconstrained_max_quota_buffer_size =
     "Discard the cap on the max free pool size for one memory allocator";
 const char* const additional_constraints_unconstrained_max_quota_buffer_size =
     "{}";
-const char* const description_work_serializer_clears_time_cache =
-    "Have the work serializer clear the time cache when it dispatches work.";
-const char* const additional_constraints_work_serializer_clears_time_cache =
-    "{}";
 const char* const description_work_serializer_dispatch =
     "Have the work serializer dispatch work to event engine for every "
     "callback, instead of running things inline in the first thread that "
@@ -159,10 +155,6 @@ const ExperimentMetadata g_experiment_metadata[] = {
      description_unconstrained_max_quota_buffer_size,
      additional_constraints_unconstrained_max_quota_buffer_size, nullptr, 0,
      false, true},
-    {"work_serializer_clears_time_cache",
-     description_work_serializer_clears_time_cache,
-     additional_constraints_work_serializer_clears_time_cache, nullptr, 0, true,
-     true},
     {"work_serializer_dispatch", description_work_serializer_dispatch,
      additional_constraints_work_serializer_dispatch, nullptr, 0, false, true},
 };
@@ -243,10 +235,6 @@ const char* const description_unconstrained_max_quota_buffer_size =
     "Discard the cap on the max free pool size for one memory allocator";
 const char* const additional_constraints_unconstrained_max_quota_buffer_size =
     "{}";
-const char* const description_work_serializer_clears_time_cache =
-    "Have the work serializer clear the time cache when it dispatches work.";
-const char* const additional_constraints_work_serializer_clears_time_cache =
-    "{}";
 const char* const description_work_serializer_dispatch =
     "Have the work serializer dispatch work to event engine for every "
     "callback, instead of running things inline in the first thread that "
@@ -308,10 +296,6 @@ const ExperimentMetadata g_experiment_metadata[] = {
      description_unconstrained_max_quota_buffer_size,
      additional_constraints_unconstrained_max_quota_buffer_size, nullptr, 0,
      false, true},
-    {"work_serializer_clears_time_cache",
-     description_work_serializer_clears_time_cache,
-     additional_constraints_work_serializer_clears_time_cache, nullptr, 0, true,
-     true},
     {"work_serializer_dispatch", description_work_serializer_dispatch,
      additional_constraints_work_serializer_dispatch, nullptr, 0, false, true},
 };
@@ -392,10 +376,6 @@ const char* const description_unconstrained_max_quota_buffer_size =
     "Discard the cap on the max free pool size for one memory allocator";
 const char* const additional_constraints_unconstrained_max_quota_buffer_size =
     "{}";
-const char* const description_work_serializer_clears_time_cache =
-    "Have the work serializer clear the time cache when it dispatches work.";
-const char* const additional_constraints_work_serializer_clears_time_cache =
-    "{}";
 const char* const description_work_serializer_dispatch =
     "Have the work serializer dispatch work to event engine for every "
     "callback, instead of running things inline in the first thread that "
@@ -457,10 +437,6 @@ const ExperimentMetadata g_experiment_metadata[] = {
      description_unconstrained_max_quota_buffer_size,
      additional_constraints_unconstrained_max_quota_buffer_size, nullptr, 0,
      false, true},
-    {"work_serializer_clears_time_cache",
-     description_work_serializer_clears_time_cache,
-     additional_constraints_work_serializer_clears_time_cache, nullptr, 0, true,
-     true},
     {"work_serializer_dispatch", description_work_serializer_dispatch,
      additional_constraints_work_serializer_dispatch, nullptr, 0, true, true},
 };

src/core/lib/experiments/experiments.h

@@ -84,8 +84,6 @@ inline bool IsTimeCachingInPartyEnabled() { return true; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_TRACE_RECORD_CALLOPS
 inline bool IsTraceRecordCallopsEnabled() { return true; }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() { return false; }
-#define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_CLEARS_TIME_CACHE
-inline bool IsWorkSerializerClearsTimeCacheEnabled() { return true; }
 inline bool IsWorkSerializerDispatchEnabled() { return false; }
 
 #elif defined(GPR_WINDOWS)
@@ -119,8 +117,6 @@ inline bool IsTimeCachingInPartyEnabled() { return true; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_TRACE_RECORD_CALLOPS
 inline bool IsTraceRecordCallopsEnabled() { return true; }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() { return false; }
-#define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_CLEARS_TIME_CACHE
-inline bool IsWorkSerializerClearsTimeCacheEnabled() { return true; }
 inline bool IsWorkSerializerDispatchEnabled() { return false; }
 
 #else
@@ -153,8 +149,6 @@ inline bool IsTimeCachingInPartyEnabled() { return true; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_TRACE_RECORD_CALLOPS
 inline bool IsTraceRecordCallopsEnabled() { return true; }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() { return false; }
-#define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_CLEARS_TIME_CACHE
-inline bool IsWorkSerializerClearsTimeCacheEnabled() { return true; }
 #define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_DISPATCH
 inline bool IsWorkSerializerDispatchEnabled() { return true; }
 #endif
@@ -182,7 +176,6 @@ enum ExperimentIds {
   kExperimentIdTimeCachingInParty,
   kExperimentIdTraceRecordCallops,
   kExperimentIdUnconstrainedMaxQuotaBufferSize,
-  kExperimentIdWorkSerializerClearsTimeCache,
   kExperimentIdWorkSerializerDispatch,
   kNumExperiments
 };
@@ -270,10 +263,6 @@ inline bool IsTraceRecordCallopsEnabled() {
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() {
   return IsExperimentEnabled<kExperimentIdUnconstrainedMaxQuotaBufferSize>();
 }
-#define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_CLEARS_TIME_CACHE
-inline bool IsWorkSerializerClearsTimeCacheEnabled() {
-  return IsExperimentEnabled<kExperimentIdWorkSerializerClearsTimeCache>();
-}
 #define GRPC_EXPERIMENT_IS_INCLUDED_WORK_SERIALIZER_DISPATCH
 inline bool IsWorkSerializerDispatchEnabled() {
   return IsExperimentEnabled<kExperimentIdWorkSerializerDispatch>();

src/core/lib/experiments/experiments.yaml

@@ -165,12 +165,6 @@
   expiry: 2024/09/09
   owner: ctiller@google.com
   test_tags: [resource_quota_test]
-- name: work_serializer_clears_time_cache
-  description:
-    Have the work serializer clear the time cache when it dispatches work.
-  expiry: 2024/10/01
-  owner: ctiller@google.com
-  test_tags: []
 - name: work_serializer_dispatch
   description:
     Have the work serializer dispatch work to event engine for every callback,

src/core/util/work_serializer.cc

@@ -243,9 +243,6 @@ void WorkSerializer::LegacyWorkSerializer::DrainQueueOwned() {
     }
     // There is at least one callback on the queue. Pop the callback from the
     // queue and execute it.
-    if (IsWorkSerializerClearsTimeCacheEnabled() && ExecCtx::Get() != nullptr) {
-      ExecCtx::Get()->InvalidateNow();
-    }
     CallbackWrapper* cb_wrapper = nullptr;
     bool empty_unused;
     while ((cb_wrapper = reinterpret_cast<CallbackWrapper*>(