diff --git a/BUILD b/BUILD
index 4de00bb125f..1c887345b0c 100644
--- a/BUILD
+++ b/BUILD
@@ -512,6 +512,7 @@ grpc_cc_library(
         "src/core/lib/iomgr/tcp_windows.c",
         "src/core/lib/iomgr/time_averaged_stats.c",
         "src/core/lib/iomgr/timer_generic.c",
+        "src/core/lib/iomgr/timer_manager.c",
         "src/core/lib/iomgr/timer_heap.c",
         "src/core/lib/iomgr/timer_uv.c",
         "src/core/lib/iomgr/udp_server.c",
@@ -632,6 +633,7 @@ grpc_cc_library(
         "src/core/lib/iomgr/time_averaged_stats.h",
         "src/core/lib/iomgr/timer.h",
         "src/core/lib/iomgr/timer_generic.h",
+        "src/core/lib/iomgr/timer_manager.h",
         "src/core/lib/iomgr/timer_heap.h",
         "src/core/lib/iomgr/timer_uv.h",
         "src/core/lib/iomgr/udp_server.h",
diff --git a/src/core/ext/filters/http/server/http_server_filter.c b/src/core/ext/filters/http/server/http_server_filter.c
index ff857878e46..9e495f4d422 100644
--- a/src/core/ext/filters/http/server/http_server_filter.c
+++ b/src/core/ext/filters/http/server/http_server_filter.c
@@ -46,8 +46,6 @@
 #define EXPECTED_CONTENT_TYPE "application/grpc"
 #define EXPECTED_CONTENT_TYPE_LENGTH sizeof(EXPECTED_CONTENT_TYPE) - 1
 
-extern int grpc_http_trace;
-
 typedef struct call_data {
   grpc_linked_mdelem status;
   grpc_linked_mdelem content_type;
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.c b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
index 8fdd4ee77c1..126e012aac9 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
@@ -69,7 +69,7 @@ static grpc_slice_refcount terminal_slice_refcount = {NULL, NULL};
 static const grpc_slice terminal_slice = {&terminal_slice_refcount,
                                           .data.refcounted = {0, 0}};
 
-extern int grpc_http_trace;
+extern grpc_tracer_flag grpc_http_trace;
 
 typedef struct {
   int is_first_frame;
@@ -425,7 +425,7 @@ static void hpack_enc(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
         "Reserved header (colon-prefixed) happening after regular ones.");
   }
 
-  if (grpc_http_trace && !GRPC_MDELEM_IS_INTERNED(elem)) {
+  if (GRPC_TRACER_ON(grpc_http_trace) && !GRPC_MDELEM_IS_INTERNED(elem)) {
     char *k = grpc_slice_to_c_string(GRPC_MDKEY(elem));
     char *v = grpc_slice_to_c_string(GRPC_MDVALUE(elem));
     gpr_log(
@@ -616,7 +616,7 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
     }
   }
   c->advertise_table_size_change = 1;
-  if (grpc_http_trace) {
+  if (GRPC_TRACER_ON(grpc_http_trace)) {
     gpr_log(GPR_DEBUG, "set max table size from encoder to %d", max_table_size);
   }
 }
diff --git a/src/core/ext/transport/chttp2/transport/hpack_table.c b/src/core/ext/transport/chttp2/transport/hpack_table.c
index 9dd41fdbe16..7aaff553396 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_table.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_table.c
@@ -40,9 +40,10 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/lib/debug/trace.h"
 #include "src/core/lib/support/murmur_hash.h"
 
-extern int grpc_http_trace;
+extern grpc_tracer_flag grpc_http_trace;
 
 static struct {
   const char *key;
@@ -260,7 +261,7 @@ void grpc_chttp2_hptbl_set_max_bytes(grpc_exec_ctx *exec_ctx,
   if (tbl->max_bytes == max_bytes) {
     return;
   }
-  if (grpc_http_trace) {
+  if (GRPC_TRACER_ON(grpc_http_trace)) {
     gpr_log(GPR_DEBUG, "Update hpack parser max size to %d", max_bytes);
   }
   while (tbl->mem_used > max_bytes) {
@@ -284,7 +285,7 @@ grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_exec_ctx *exec_ctx,
     gpr_free(msg);
     return err;
   }
-  if (grpc_http_trace) {
+  if (GRPC_TRACER_ON(grpc_http_trace)) {
     gpr_log(GPR_DEBUG, "Update hpack parser table size to %d", bytes);
   }
   while (tbl->mem_used > bytes) {
diff --git a/src/core/lib/iomgr/tcp_client_uv.c b/src/core/lib/iomgr/tcp_client_uv.c
index 682c24ed56b..f0856a76d4b 100644
--- a/src/core/lib/iomgr/tcp_client_uv.c
+++ b/src/core/lib/iomgr/tcp_client_uv.c
@@ -46,7 +46,7 @@
 #include "src/core/lib/iomgr/tcp_uv.h"
 #include "src/core/lib/iomgr/timer.h"
 
-extern int grpc_tcp_trace;
+extern grpc_tracer_flag grpc_tcp_trace;
 
 typedef struct grpc_uv_tcp_connect {
   uv_connect_t connect_req;
@@ -72,7 +72,7 @@ static void uv_tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp,
                            grpc_error *error) {
   int done;
   grpc_uv_tcp_connect *connect = acp;
-  if (grpc_tcp_trace) {
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_alarm: error=%s",
             connect->addr_name, str);
@@ -156,7 +156,7 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
   uv_tcp_init(uv_default_loop(), connect->tcp_handle);
   connect->connect_req.data = connect;
 
-  if (grpc_tcp_trace) {
+  if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: asynchronously connecting",
             connect->addr_name);
   }
diff --git a/src/core/lib/iomgr/tcp_uv.h b/src/core/lib/iomgr/tcp_uv.h
index 970fcafe4a5..106bec5eca7 100644
--- a/src/core/lib/iomgr/tcp_uv.h
+++ b/src/core/lib/iomgr/tcp_uv.h
@@ -44,11 +44,12 @@
    otherwise specified.
 */
 
+#include "src/core/lib/debug/trace.h"
 #include "src/core/lib/iomgr/endpoint.h"
 
 #include <uv.h>
 
-extern int grpc_tcp_trace;
+extern grpc_tracer_flag grpc_tcp_trace;
 
 #define GRPC_TCP_DEFAULT_READ_SLICE_SIZE 8192
 
diff --git a/src/core/lib/iomgr/timer_manager.c b/src/core/lib/iomgr/timer_manager.c
index 1d83341299e..464907b4546 100644
--- a/src/core/lib/iomgr/timer_manager.c
+++ b/src/core/lib/iomgr/timer_manager.c
@@ -44,16 +44,26 @@ typedef struct completed_thread {
   struct completed_thread *next;
 } completed_thread;
 
+// global mutex
 static gpr_mu g_mu;
+// are we multi-threaded
 static bool g_threaded;
+// cv to wait until a thread is needed
 static gpr_cv g_cv_wait;
+// cv for notification when threading ends
 static gpr_cv g_cv_shutdown;
+// number of threads in the system
 static int g_thread_count;
+// number of threads sitting around waiting
 static int g_waiter_count;
+// linked list of threads that have completed (and need joining)
 static completed_thread *g_completed_threads;
+// was the manager kicked by the timer system
 static bool g_kicked;
-
-#define MAX_WAITERS 3
+// is there a thread waiting until the next timer should fire?
+static bool g_has_timed_waiter;
+// generation counter to track which thread is waiting for the next timer
+static uint64_t g_timed_waiter_generation;
 
 static void timer_thread(void *unused);
 
@@ -92,39 +102,79 @@ void grpc_timer_manager_tick() {
 }
 
 static void timer_thread(void *unused) {
+  // this threads exec_ctx: we try to run things through to completion here
+  // since it's easy to spin up new threads
   grpc_exec_ctx exec_ctx =
       GRPC_EXEC_CTX_INITIALIZER(0, grpc_never_ready_to_finish, NULL);
+  const gpr_timespec inf_future = gpr_inf_future(GPR_CLOCK_MONOTONIC);
   for (;;) {
-    gpr_timespec next = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+    gpr_timespec next = inf_future;
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+    // check timer state, updates next to the next time to run a check
     if (grpc_timer_check(&exec_ctx, now, &next)) {
+      // if there's something to execute...
       gpr_mu_lock(&g_mu);
+      // remove a waiter from the pool, and start another thread if necessary
       --g_waiter_count;
-      bool start_thread = g_waiter_count == 0;
-      if (start_thread && g_threaded) {
+      if (g_waiter_count == 0 && g_threaded) {
         start_timer_thread_and_unlock();
       } else {
+        // if there's no thread waiting with a timeout, kick an existing waiter
+        // so that the next deadline is not missed
+        if (!g_has_timed_waiter) {
+          gpr_log(GPR_DEBUG, "kick untimed waiter");
+          gpr_cv_signal(&g_cv_wait);
+        }
         gpr_mu_unlock(&g_mu);
       }
+      // without our lock, flush the exec_ctx
       grpc_exec_ctx_flush(&exec_ctx);
       gpr_mu_lock(&g_mu);
+      // garbage collect any threads hanging out that are dead
       gc_completed_threads();
+      // get ready to wait again
       ++g_waiter_count;
       gpr_mu_unlock(&g_mu);
     } else {
       gpr_mu_lock(&g_mu);
+      // if we're not threaded anymore, leave
       if (!g_threaded) break;
-      if (gpr_cv_wait(&g_cv_wait, &g_mu, next)) {
-        if (g_kicked) {
-          grpc_timer_consume_kick();
-          g_kicked = false;
-        } else if (g_waiter_count > MAX_WAITERS) {
-          break;
-        }
+      // if there's no timed waiter, we should become one: that waiter waits
+      // only until the next timer should expire
+      // all other timers wait forever
+      uint64_t my_timed_waiter_generation = g_timed_waiter_generation - 1;
+      if (!g_has_timed_waiter) {
+        g_has_timed_waiter = true;
+        // we use a generation counter to track the timed waiter so we can
+        // cancel an existing one quickly (and when it actually times out it'll
+        // figure stuff out instead of incurring a wakeup)
+        my_timed_waiter_generation = ++g_timed_waiter_generation;
+        gpr_log(GPR_DEBUG, "sleep for a while");
+      } else {
+        next = inf_future;
+        gpr_log(GPR_DEBUG, "sleep until kicked");
+      }
+      gpr_cv_wait(&g_cv_wait, &g_mu, next);
+      gpr_log(GPR_DEBUG, "wait ended: was_timed:%d kicked:%d",
+              my_timed_waiter_generation == g_timed_waiter_generation,
+              g_kicked);
+      // if this was the timed waiter, then we need to check timers, and flag
+      // that there's now no timed waiter... we'll look for a replacement if
+      // there's work to do after checking timers (code above)
+      if (my_timed_waiter_generation == g_timed_waiter_generation) {
+        g_has_timed_waiter = false;
+      }
+      // if this was a kick from the timer system, consume it (and don't stop
+      // this thread yet)
+      if (g_kicked) {
+        grpc_timer_consume_kick();
+        g_kicked = false;
       }
-      gpr_mu_unlock(&g_mu);
     }
+    gpr_mu_unlock(&g_mu);
   }
+  // terminate the thread: drop the waiter count, thread count, and let whomever
+  // stopped the threading stuff know that we're done
   --g_waiter_count;
   --g_thread_count;
   if (0 == g_thread_count) {
@@ -135,6 +185,7 @@ static void timer_thread(void *unused) {
   ct->next = g_completed_threads;
   g_completed_threads = ct;
   gpr_mu_unlock(&g_mu);
+  grpc_exec_ctx_finish(&exec_ctx);
   gpr_log(GPR_DEBUG, "End timer thread");
 }
 
@@ -193,6 +244,8 @@ void grpc_timer_manager_set_threading(bool threaded) {
 void grpc_kick_poller(void) {
   gpr_mu_lock(&g_mu);
   g_kicked = true;
+  g_has_timed_waiter = false;
+  ++g_timed_waiter_generation;
   gpr_cv_signal(&g_cv_wait);
   gpr_mu_unlock(&g_mu);
 }
diff --git a/test/core/iomgr/timer_list_test.c b/test/core/iomgr/timer_list_test.c
index 46e41dd4490..88a9f6b8556 100644
--- a/test/core/iomgr/timer_list_test.c
+++ b/test/core/iomgr/timer_list_test.c
@@ -41,12 +41,13 @@
 #include <string.h>
 
 #include <grpc/support/log.h>
+#include "src/core/lib/debug/trace.h"
 #include "test/core/util/test_config.h"
 
 #define MAX_CB 30
 
-extern int grpc_timer_trace;
-extern int grpc_timer_check_trace;
+extern grpc_tracer_flag grpc_timer_trace;
+extern grpc_tracer_flag grpc_timer_check_trace;
 
 static int cb_called[MAX_CB][2];
 
@@ -63,8 +64,8 @@ static void add_test(void) {
   gpr_log(GPR_INFO, "add_test");
 
   grpc_timer_list_init(start);
-  grpc_timer_trace = 1;
-  grpc_timer_check_trace = 1;
+  grpc_timer_trace.value = 1;
+  grpc_timer_check_trace.value = 1;
   memset(cb_called, 0, sizeof(cb_called));
 
   /* 10 ms timers.  will expire in the current epoch */
@@ -138,8 +139,8 @@ void destruction_test(void) {
   gpr_log(GPR_INFO, "destruction_test");
 
   grpc_timer_list_init(gpr_time_0(GPR_CLOCK_REALTIME));
-  grpc_timer_trace = 1;
-  grpc_timer_check_trace = 1;
+  grpc_timer_trace.value = 1;
+  grpc_timer_check_trace.value = 1;
   memset(cb_called, 0, sizeof(cb_called));
 
   grpc_timer_init(