Merge branch 'master' into sreek-epoll1

37 files changed, 169 insertions, 92 deletions

diff --git a/src/core/lib/channel/channel_stack.c b/src/core/lib/channel/channel_stack.c
index 106666410a..0f8e33c4be 100644
--- a/src/core/lib/channel/channel_stack.c
+++ b/src/core/lib/channel/channel_stack.c
@@ -23,7 +23,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-grpc_tracer_flag grpc_trace_channel = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_channel = GRPC_TRACER_INITIALIZER(false, "channel");
 
 /* Memory layouts.
 
diff --git a/src/core/lib/channel/channel_stack_builder.c b/src/core/lib/channel/channel_stack_builder.c
index 01529df80a..c369e33073 100644
--- a/src/core/lib/channel/channel_stack_builder.c
+++ b/src/core/lib/channel/channel_stack_builder.c
@@ -24,7 +24,7 @@
 #include <grpc/support/string_util.h>
 
 grpc_tracer_flag grpc_trace_channel_stack_builder =
-    GRPC_TRACER_INITIALIZER(false);
+    GRPC_TRACER_INITIALIZER(false, "channel_stack_builder");
 
 typedef struct filter_node {
   struct filter_node *next;
diff --git a/src/core/lib/debug/trace.c b/src/core/lib/debug/trace.c
index 8249b2ebd6..c6c1853e20 100644
--- a/src/core/lib/debug/trace.c
+++ b/src/core/lib/debug/trace.c
@@ -27,7 +27,6 @@
 int grpc_tracer_set_enabled(const char *name, int enabled);
 
 typedef struct tracer {
-  const char *name;
   grpc_tracer_flag *flag;
   struct tracer *next;
 } tracer;
@@ -39,9 +38,8 @@ static tracer *tracers;
 #define TRACER_SET(flag, on) (flag).value = (on)
 #endif
 
-void grpc_register_tracer(const char *name, grpc_tracer_flag *flag) {
+void grpc_register_tracer(grpc_tracer_flag *flag) {
   tracer *t = gpr_malloc(sizeof(*t));
-  t->name = name;
   t->flag = flag;
   t->next = tracers;
   TRACER_SET(*flag, false);
@@ -93,6 +91,14 @@ static void parse(const char *s) {
   gpr_free(strings);
 }
 
+static void list_tracers() {
+  gpr_log(GPR_DEBUG, "available tracers:");
+  tracer *t;
+  for (t = tracers; t; t = t->next) {
+    gpr_log(GPR_DEBUG, "\t%s", t->flag->name);
+  }
+}
+
 void grpc_tracer_init(const char *env_var) {
   char *e = gpr_getenv(env_var);
   if (e != NULL) {
@@ -115,10 +121,18 @@ int grpc_tracer_set_enabled(const char *name, int enabled) {
     for (t = tracers; t; t = t->next) {
       TRACER_SET(*t->flag, enabled);
     }
+  } else if (0 == strcmp(name, "list_tracers")) {
+    list_tracers();
+  } else if (0 == strcmp(name, "refcount")) {
+    for (t = tracers; t; t = t->next) {
+      if (strstr(t->flag->name, "refcount") != NULL) {
+        TRACER_SET(*t->flag, enabled);
+      }
+    }
   } else {
     int found = 0;
     for (t = tracers; t; t = t->next) {
-      if (0 == strcmp(name, t->name)) {
+      if (0 == strcmp(name, t->flag->name)) {
         TRACER_SET(*t->flag, enabled);
         found = 1;
       }
diff --git a/src/core/lib/debug/trace.h b/src/core/lib/debug/trace.h
index 7cc9fb4e41..dd9e6a30fe 100644
--- a/src/core/lib/debug/trace.h
+++ b/src/core/lib/debug/trace.h
@@ -35,19 +35,20 @@ typedef struct {
 #else
   bool value;
 #endif
+  char *name;
 } grpc_tracer_flag;
 
 #ifdef GRPC_THREADSAFE_TRACER
 #define GRPC_TRACER_ON(flag) (gpr_atm_no_barrier_load(&(flag).value) != 0)
-#define GRPC_TRACER_INITIALIZER(on) \
-  { (gpr_atm)(on) }
+#define GRPC_TRACER_INITIALIZER(on, name) \
+  { (gpr_atm)(on), (name) }
 #else
 #define GRPC_TRACER_ON(flag) ((flag).value)
-#define GRPC_TRACER_INITIALIZER(on) \
-  { (on) }
+#define GRPC_TRACER_INITIALIZER(on, name) \
+  { (on), (name) }
 #endif
 
-void grpc_register_tracer(const char *name, grpc_tracer_flag *flag);
+void grpc_register_tracer(grpc_tracer_flag *flag);
 void grpc_tracer_init(const char *env_var_name);
 void grpc_tracer_shutdown(void);
 
diff --git a/src/core/lib/http/parser.c b/src/core/lib/http/parser.c
index 71d697c278..9c5e93f4e5 100644
--- a/src/core/lib/http/parser.c
+++ b/src/core/lib/http/parser.c
@@ -25,7 +25,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/useful.h>
 
-grpc_tracer_flag grpc_http1_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_http1_trace = GRPC_TRACER_INITIALIZER(false, "http1");
 
 static char *buf2str(void *buffer, size_t length) {
   char *out = gpr_malloc(length + 1);
diff --git a/src/core/lib/iomgr/OWNERS b/src/core/lib/iomgr/OWNERS
new file mode 100644
index 0000000000..8ee86c2618
--- /dev/null
+++ b/src/core/lib/iomgr/OWNERS
@@ -0,0 +1 @@
+@murgatroid99 *_uv.c *_uv.h
diff --git a/src/core/lib/iomgr/closure.c b/src/core/lib/iomgr/closure.c
index e028e72ed6..26f9cbe0fa 100644
--- a/src/core/lib/iomgr/closure.c
+++ b/src/core/lib/iomgr/closure.c
@@ -25,7 +25,7 @@
 #include "src/core/lib/profiling/timers.h"
 
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_closure = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_closure = GRPC_TRACER_INITIALIZER(false, "closure");
 #endif
 
 #ifndef NDEBUG
diff --git a/src/core/lib/iomgr/combiner.c b/src/core/lib/iomgr/combiner.c
index 7f9c5d837f..c72c37e2b5 100644
--- a/src/core/lib/iomgr/combiner.c
+++ b/src/core/lib/iomgr/combiner.c
@@ -27,7 +27,8 @@
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/profiling/timers.h"
 
-grpc_tracer_flag grpc_combiner_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_combiner_trace =
+    GRPC_TRACER_INITIALIZER(false, "combiner");
 
 #define GRPC_COMBINER_TRACE(fn)                \
   do {                                         \
diff --git a/src/core/lib/iomgr/error.c b/src/core/lib/iomgr/error.c
index a95929a1fb..3759dda992 100644
--- a/src/core/lib/iomgr/error.c
+++ b/src/core/lib/iomgr/error.c
@@ -36,7 +36,8 @@
 #include "src/core/lib/slice/slice_internal.h"
 
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_error_refcount = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_error_refcount =
+    GRPC_TRACER_INITIALIZER(false, "error_refcount");
 #endif
 
 static const char *error_int_name(grpc_error_ints key) {
diff --git a/src/core/lib/iomgr/ev_epollex_linux.c b/src/core/lib/iomgr/ev_epollex_linux.c
index ceecff7a88..2499417356 100644
--- a/src/core/lib/iomgr/ev_epollex_linux.c
+++ b/src/core/lib/iomgr/ev_epollex_linux.c
@@ -103,6 +103,32 @@ typedef struct pollable {
   grpc_pollset_worker *root_worker;
 } pollable;
 
+static const char *polling_obj_type_string(polling_obj_type t) {
+  switch (t) {
+    case PO_POLLING_GROUP:
+      return "polling_group";
+    case PO_POLLSET_SET:
+      return "pollset_set";
+    case PO_POLLSET:
+      return "pollset";
+    case PO_FD:
+      return "fd";
+    case PO_EMPTY_POLLABLE:
+      return "empty_pollable";
+    case PO_COUNT:
+      return "<invalid:count>";
+  }
+  return "<invalid>";
+}
+
+static char *pollable_desc(pollable *p) {
+  char *out;
+  gpr_asprintf(&out, "type=%s group=%p epfd=%d wakeup=%d",
+               polling_obj_type_string(p->po.type), p->po.group, p->epfd,
+               p->wakeup.read_fd);
+  return out;
+}
+
 static pollable g_empty_pollable;
 
 static void pollable_init(pollable *p, polling_obj_type type);
@@ -472,7 +498,7 @@ static grpc_error *pollable_add_fd(pollable *p, grpc_fd *fd) {
   GPR_ASSERT(epfd != -1);
 
   if (GRPC_TRACER_ON(grpc_polling_trace)) {
-    gpr_log(GPR_DEBUG, "add fd %p to pollable %p", fd, p);
+    gpr_log(GPR_DEBUG, "add fd %p (%d) to pollable %p", fd, fd->fd, p);
   }
 
   gpr_mu_lock(&fd->orphaned_mu);
@@ -537,10 +563,18 @@ static void do_kick_all(grpc_exec_ctx *exec_ctx, void *arg,
       if (worker->pollable != &pollset->pollable) {
         gpr_mu_lock(&worker->pollable->po.mu);
       }
-      if (worker->initialized_cv) {
+      if (worker->initialized_cv && worker != pollset->root_worker) {
+        if (GRPC_TRACER_ON(grpc_polling_trace)) {
+          gpr_log(GPR_DEBUG, "PS:%p kickall_via_cv %p (pollable %p vs %p)",
+                  pollset, worker, &pollset->pollable, worker->pollable);
+        }
         worker->kicked = true;
         gpr_cv_signal(&worker->cv);
       } else {
+        if (GRPC_TRACER_ON(grpc_polling_trace)) {
+          gpr_log(GPR_DEBUG, "PS:%p kickall_via_wakeup %p (pollable %p vs %p)",
+                  pollset, worker, &pollset->pollable, worker->pollable);
+        }
         append_error(&error, grpc_wakeup_fd_wakeup(&worker->pollable->wakeup),
                      "pollset_shutdown");
       }
@@ -770,7 +804,9 @@ static grpc_error *pollset_epoll(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   int timeout = poll_deadline_to_millis_timeout(deadline, now);
 
   if (GRPC_TRACER_ON(grpc_polling_trace)) {
-    gpr_log(GPR_DEBUG, "PS:%p poll %p for %dms", pollset, p, timeout);
+    char *desc = pollable_desc(p);
+    gpr_log(GPR_DEBUG, "PS:%p poll %p[%s] for %dms", pollset, p, desc, timeout);
+    gpr_free(desc);
   }
 
   if (timeout != 0) {
@@ -985,10 +1021,11 @@ static grpc_error *pollset_add_fd_locked(grpc_exec_ctx *exec_ctx,
   static const char *err_desc = "pollset_add_fd";
   grpc_error *error = GRPC_ERROR_NONE;
   if (pollset->current_pollable == &g_empty_pollable) {
-    if (GRPC_TRACER_ON(grpc_polling_trace))
+    if (GRPC_TRACER_ON(grpc_polling_trace)) {
       gpr_log(GPR_DEBUG,
               "PS:%p add fd %p; transition pollable from empty to fd", pollset,
               fd);
+    }
     /* empty pollable --> single fd pollable */
     pollset_kick_all(exec_ctx, pollset);
     pollset->current_pollable = &fd->pollable;
@@ -997,16 +1034,23 @@ static grpc_error *pollset_add_fd_locked(grpc_exec_ctx *exec_ctx,
     if (!fd_locked) gpr_mu_unlock(&fd->pollable.po.mu);
     REF_BY(fd, 2, "pollset_pollable");
   } else if (pollset->current_pollable == &pollset->pollable) {
-    if (GRPC_TRACER_ON(grpc_polling_trace))
+    if (GRPC_TRACER_ON(grpc_polling_trace)) {
       gpr_log(GPR_DEBUG, "PS:%p add fd %p; already multipolling", pollset, fd);
+    }
     append_error(&error, pollable_add_fd(pollset->current_pollable, fd),
                  err_desc);
   } else if (pollset->current_pollable != &fd->pollable) {
     grpc_fd *had_fd = (grpc_fd *)pollset->current_pollable;
-    if (GRPC_TRACER_ON(grpc_polling_trace))
+    if (GRPC_TRACER_ON(grpc_polling_trace)) {
       gpr_log(GPR_DEBUG,
               "PS:%p add fd %p; transition pollable from fd %p to multipoller",
               pollset, fd, had_fd);
+    }
+    /* Introduce a spurious completion.
+       If we do not, then it may be that the fd-specific epoll set consumed
+       a completion without being polled, leading to a missed edge going up. */
+    grpc_lfev_set_ready(exec_ctx, &had_fd->read_closure);
+    grpc_lfev_set_ready(exec_ctx, &had_fd->write_closure);
     pollset_kick_all(exec_ctx, pollset);
     pollset->current_pollable = &pollset->pollable;
     if (append_error(&error, pollable_materialize(&pollset->pollable),
diff --git a/src/core/lib/iomgr/ev_posix.c b/src/core/lib/iomgr/ev_posix.c
index 2648df393d..a5ae04cb5b 100644
--- a/src/core/lib/iomgr/ev_posix.c
+++ b/src/core/lib/iomgr/ev_posix.c
@@ -39,10 +39,11 @@
 #include "src/core/lib/support/env.h"
 
 grpc_tracer_flag grpc_polling_trace =
-    GRPC_TRACER_INITIALIZER(false); /* Disabled by default */
+    GRPC_TRACER_INITIALIZER(false, "polling"); /* Disabled by default */
 
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_fd_refcount = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_fd_refcount =
+    GRPC_TRACER_INITIALIZER(false, "fd_refcount");
 #endif
 
 /** Default poll() function - a pointer so that it can be overridden by some
@@ -124,7 +125,7 @@ void grpc_set_event_engine_test_only(
 const char *grpc_get_poll_strategy_name() { return g_poll_strategy_name; }
 
 void grpc_event_engine_init(void) {
-  grpc_register_tracer("polling", &grpc_polling_trace);
+  grpc_register_tracer(&grpc_polling_trace);
 
   char *s = gpr_getenv("GRPC_POLL_STRATEGY");
   if (s == NULL) {
diff --git a/src/core/lib/iomgr/ev_windows.c b/src/core/lib/iomgr/ev_windows.c
index 027609c7e8..c24dfaeaf7 100644
--- a/src/core/lib/iomgr/ev_windows.c
+++ b/src/core/lib/iomgr/ev_windows.c
@@ -23,6 +23,6 @@
 #include "src/core/lib/debug/trace.h"
 
 grpc_tracer_flag grpc_polling_trace =
-    GRPC_TRACER_INITIALIZER(false); /* Disabled by default */
+    GRPC_TRACER_INITIALIZER(false, "polling"); /* Disabled by default */
 
 #endif  // GRPC_WINSOCK_SOCKET
diff --git a/src/core/lib/iomgr/iomgr_posix.c b/src/core/lib/iomgr/iomgr_posix.c
index 43f5d0406e..f5875a247e 100644
--- a/src/core/lib/iomgr/iomgr_posix.c
+++ b/src/core/lib/iomgr/iomgr_posix.c
@@ -28,7 +28,7 @@
 void grpc_iomgr_platform_init(void) {
   grpc_wakeup_fd_global_init();
   grpc_event_engine_init();
-  grpc_register_tracer("tcp", &grpc_tcp_trace);
+  grpc_register_tracer(&grpc_tcp_trace);
 }
 
 void grpc_iomgr_platform_flush(void) {}
diff --git a/src/core/lib/iomgr/iomgr_uv.c b/src/core/lib/iomgr/iomgr_uv.c
index 49d1a03c32..8b1245c640 100644
--- a/src/core/lib/iomgr/iomgr_uv.c
+++ b/src/core/lib/iomgr/iomgr_uv.c
@@ -26,7 +26,7 @@
 
 void grpc_iomgr_platform_init(void) {
   grpc_pollset_global_init();
-  grpc_register_tracer("tcp", &grpc_tcp_trace);
+  grpc_register_tracer(&grpc_tcp_trace);
 }
 void grpc_iomgr_platform_flush(void) {}
 void grpc_iomgr_platform_shutdown(void) { grpc_pollset_global_shutdown(); }
diff --git a/src/core/lib/iomgr/pollset_uv.c b/src/core/lib/iomgr/pollset_uv.c
index 1a54065a91..946f0c8c60 100644
--- a/src/core/lib/iomgr/pollset_uv.c
+++ b/src/core/lib/iomgr/pollset_uv.c
@@ -34,7 +34,8 @@
 #include "src/core/lib/debug/trace.h"
 
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_fd_refcount = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_fd_refcount =
+    GRPC_TRACER_INITIALIZER(false, "fd_refcount");
 #endif
 
 struct grpc_pollset {
diff --git a/src/core/lib/iomgr/pollset_windows.c b/src/core/lib/iomgr/pollset_windows.c
index 1bfc2a22a8..ea017a6054 100644
--- a/src/core/lib/iomgr/pollset_windows.c
+++ b/src/core/lib/iomgr/pollset_windows.c
@@ -31,7 +31,8 @@
 #define GRPC_POLLSET_KICK_BROADCAST ((grpc_pollset_worker *)1)
 
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_fd_refcount = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_fd_refcount =
+    GRPC_TRACER_INITIALIZER(false, "fd_refcount");
 #endif
 
 gpr_mu grpc_polling_mu;
diff --git a/src/core/lib/iomgr/resource_quota.c b/src/core/lib/iomgr/resource_quota.c
index f2cc1be74e..a31d9eef93 100644
--- a/src/core/lib/iomgr/resource_quota.c
+++ b/src/core/lib/iomgr/resource_quota.c
@@ -29,7 +29,8 @@
 
 #include "src/core/lib/iomgr/combiner.h"
 
-grpc_tracer_flag grpc_resource_quota_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_resource_quota_trace =
+    GRPC_TRACER_INITIALIZER(false, "resource_quota");
 
 #define MEMORY_USAGE_ESTIMATION_MAX 65536
 
diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.c
index 5de2b0f4ee..b6dcd15cb0 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.c
@@ -59,7 +59,7 @@ typedef GRPC_MSG_IOVLEN_TYPE msg_iovlen_type;
 typedef size_t msg_iovlen_type;
 #endif
 
-grpc_tracer_flag grpc_tcp_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_tcp_trace = GRPC_TRACER_INITIALIZER(false, "tcp");
 
 typedef struct {
   grpc_endpoint base;
diff --git a/src/core/lib/iomgr/tcp_uv.c b/src/core/lib/iomgr/tcp_uv.c
index ff5fd3edc8..7c6a9b85f5 100644
--- a/src/core/lib/iomgr/tcp_uv.c
+++ b/src/core/lib/iomgr/tcp_uv.c
@@ -37,7 +37,7 @@
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 
-grpc_tracer_flag grpc_tcp_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_tcp_trace = GRPC_TRACER_INITIALIZER(false, "tcp");
 
 typedef struct {
   grpc_endpoint base;
diff --git a/src/core/lib/iomgr/tcp_windows.c b/src/core/lib/iomgr/tcp_windows.c
index 6704a158ce..2cbb97403b 100644
--- a/src/core/lib/iomgr/tcp_windows.c
+++ b/src/core/lib/iomgr/tcp_windows.c
@@ -48,7 +48,7 @@
 #define GRPC_FIONBIO FIONBIO
 #endif
 
-grpc_tracer_flag grpc_tcp_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_tcp_trace = GRPC_TRACER_INITIALIZER(false, "tcp");
 
 static grpc_error *set_non_block(SOCKET sock) {
   int status;
diff --git a/src/core/lib/iomgr/timer_generic.c b/src/core/lib/iomgr/timer_generic.c
index e6a9eb0e86..12efce241f 100644
--- a/src/core/lib/iomgr/timer_generic.c
+++ b/src/core/lib/iomgr/timer_generic.c
@@ -41,8 +41,9 @@
 #define MIN_QUEUE_WINDOW_DURATION 0.01
 #define MAX_QUEUE_WINDOW_DURATION 1
 
-grpc_tracer_flag grpc_timer_trace = GRPC_TRACER_INITIALIZER(false);
-grpc_tracer_flag grpc_timer_check_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_timer_trace = GRPC_TRACER_INITIALIZER(false, "timer");
+grpc_tracer_flag grpc_timer_check_trace =
+    GRPC_TRACER_INITIALIZER(false, "timer_check");
 
 /* A "timer shard". Contains a 'heap' and a 'list' of timers. All timers with
  * deadlines earlier than 'queue_deadline" cap are maintained in the heap and
@@ -160,8 +161,8 @@ void grpc_timer_list_init(gpr_timespec now) {
   g_shared_mutables.min_timer = timespec_to_atm_round_down(now);
   gpr_tls_init(&g_last_seen_min_timer);
   gpr_tls_set(&g_last_seen_min_timer, 0);
-  grpc_register_tracer("timer", &grpc_timer_trace);
-  grpc_register_tracer("timer_check", &grpc_timer_check_trace);
+  grpc_register_tracer(&grpc_timer_trace);
+  grpc_register_tracer(&grpc_timer_check_trace);
 
   for (i = 0; i < NUM_SHARDS; i++) {
     timer_shard *shard = &g_shards[i];
diff --git a/src/core/lib/iomgr/timer_manager.c b/src/core/lib/iomgr/timer_manager.c
index cb7998db97..b9bea9a2ab 100644
--- a/src/core/lib/iomgr/timer_manager.c
+++ b/src/core/lib/iomgr/timer_manager.c
@@ -56,7 +56,7 @@ static gpr_timespec g_timed_waiter_deadline;
 // 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);
+static void timer_thread(void *completed_thread_ptr);
 
 static void gc_completed_threads(void) {
   if (g_completed_threads != NULL) {
@@ -81,10 +81,10 @@ static void start_timer_thread_and_unlock(void) {
   if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
     gpr_log(GPR_DEBUG, "Spawn timer thread");
   }
-  gpr_thd_id thd;
   gpr_thd_options opt = gpr_thd_options_default();
   gpr_thd_options_set_joinable(&opt);
-  gpr_thd_new(&thd, timer_thread, NULL, &opt);
+  completed_thread *ct = gpr_malloc(sizeof(*ct));
+  gpr_thd_new(&ct->t, timer_thread, ct, &opt);
 }
 
 void grpc_timer_manager_tick() {
@@ -245,7 +245,7 @@ static void timer_main_loop(grpc_exec_ctx *exec_ctx) {
   }
 }
 
-static void timer_thread_cleanup(void) {
+static void timer_thread_cleanup(completed_thread *ct) {
   gpr_mu_lock(&g_mu);
   // terminate the thread: drop the waiter count, thread count, and let whomever
   // stopped the threading stuff know that we're done
@@ -254,8 +254,6 @@ static void timer_thread_cleanup(void) {
   if (0 == g_thread_count) {
     gpr_cv_signal(&g_cv_shutdown);
   }
-  completed_thread *ct = gpr_malloc(sizeof(*ct));
-  ct->t = gpr_thd_currentid();
   ct->next = g_completed_threads;
   g_completed_threads = ct;
   gpr_mu_unlock(&g_mu);
@@ -264,14 +262,14 @@ static void timer_thread_cleanup(void) {
   }
 }
 
-static void timer_thread(void *unused) {
+static void timer_thread(void *completed_thread_ptr) {
   // 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);
   timer_main_loop(&exec_ctx);
   grpc_exec_ctx_finish(&exec_ctx);
-  timer_thread_cleanup();
+  timer_thread_cleanup(completed_thread_ptr);
 }
 
 static void start_threads(void) {
diff --git a/src/core/lib/iomgr/timer_uv.c b/src/core/lib/iomgr/timer_uv.c
index 4f204cfbf8..1ab82ef1d5 100644
--- a/src/core/lib/iomgr/timer_uv.c
+++ b/src/core/lib/iomgr/timer_uv.c
@@ -28,8 +28,9 @@
 
 #include <uv.h>
 
-grpc_tracer_flag grpc_timer_trace = GRPC_TRACER_INITIALIZER(false);
-grpc_tracer_flag grpc_timer_check_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_timer_trace = GRPC_TRACER_INITIALIZER(false, "timer");
+grpc_tracer_flag grpc_timer_check_trace =
+    GRPC_TRACER_INITIALIZER(false, "timer_check");
 
 static void timer_close_callback(uv_handle_t *handle) { gpr_free(handle); }
 
diff --git a/src/core/lib/security/context/security_context.c b/src/core/lib/security/context/security_context.c
index dffe6d2e91..8fff2c92c5 100644
--- a/src/core/lib/security/context/security_context.c
+++ b/src/core/lib/security/context/security_context.c
@@ -31,7 +31,7 @@
 
 #ifndef NDEBUG
 grpc_tracer_flag grpc_trace_auth_context_refcount =
-    GRPC_TRACER_INITIALIZER(false);
+    GRPC_TRACER_INITIALIZER(false, "auth_context_refcount");
 #endif
 
 /* --- grpc_call --- */
diff --git a/src/core/lib/security/transport/secure_endpoint.c b/src/core/lib/security/transport/secure_endpoint.c
index f4ed81db1a..5e41b94ff8 100644
--- a/src/core/lib/security/transport/secure_endpoint.c
+++ b/src/core/lib/security/transport/secure_endpoint.c
@@ -60,7 +60,8 @@ typedef struct {
   gpr_refcount ref;
 } secure_endpoint;
 
-grpc_tracer_flag grpc_trace_secure_endpoint = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_secure_endpoint =
+    GRPC_TRACER_INITIALIZER(false, "secure_endpoint");
 
 static void destroy(grpc_exec_ctx *exec_ctx, secure_endpoint *secure_ep) {
   secure_endpoint *ep = secure_ep;
diff --git a/src/core/lib/security/transport/security_connector.c b/src/core/lib/security/transport/security_connector.c
index 29327107e5..6788126769 100644
--- a/src/core/lib/security/transport/security_connector.c
+++ b/src/core/lib/security/transport/security_connector.c
@@ -45,7 +45,7 @@
 
 #ifndef NDEBUG
 grpc_tracer_flag grpc_trace_security_connector_refcount =
-    GRPC_TRACER_INITIALIZER(false);
+    GRPC_TRACER_INITIALIZER(false, "security_connector_refcount");
 #endif
 
 /* -- Constants. -- */
diff --git a/src/core/lib/support/log_linux.c b/src/core/lib/support/log_linux.c
index 5c512661a3..61d2346427 100644
--- a/src/core/lib/support/log_linux.c
+++ b/src/core/lib/support/log_linux.c
@@ -64,6 +64,8 @@ void gpr_default_log(gpr_log_func_args *args) {
   time_t timer;
   gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
   struct tm tm;
+  static __thread long tid = 0;
+  if (tid == 0) tid = gettid();
 
   timer = (time_t)now.tv_sec;
   final_slash = strrchr(args->file, '/');
@@ -81,7 +83,7 @@ void gpr_default_log(gpr_log_func_args *args) {
 
   gpr_asprintf(&prefix, "%s%s.%09" PRId32 " %7ld %s:%d]",
                gpr_log_severity_string(args->severity), time_buffer,
-               now.tv_nsec, gettid(), display_file, args->line);
+               now.tv_nsec, tid, display_file, args->line);
 
   fprintf(stderr, "%-60s %s\n", prefix, args->message);
   gpr_free(prefix);
diff --git a/src/core/lib/surface/api_trace.c b/src/core/lib/surface/api_trace.c
index f88ffd57aa..56973303da 100644
--- a/src/core/lib/surface/api_trace.c
+++ b/src/core/lib/surface/api_trace.c
@@ -19,4 +19,4 @@
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/debug/trace.h"
 
-grpc_tracer_flag grpc_api_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_api_trace = GRPC_TRACER_INITIALIZER(false, "api");
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index aac443ed06..2365d27307 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -229,8 +229,10 @@ struct grpc_call {
   void *saved_receiving_stream_ready_bctlp;
 };
 
-grpc_tracer_flag grpc_call_error_trace = GRPC_TRACER_INITIALIZER(false);
-grpc_tracer_flag grpc_compression_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_call_error_trace =
+    GRPC_TRACER_INITIALIZER(false, "call_error");
+grpc_tracer_flag grpc_compression_trace =
+    GRPC_TRACER_INITIALIZER(false, "compression");
 
 #define CALL_STACK_FROM_CALL(call) ((grpc_call_stack *)((call) + 1))
 #define CALL_FROM_CALL_STACK(call_stack) (((grpc_call *)(call_stack)) - 1)
diff --git a/src/core/lib/surface/completion_queue.c b/src/core/lib/surface/completion_queue.c
index 14e55eda85..978d7b4171 100644
--- a/src/core/lib/surface/completion_queue.c
+++ b/src/core/lib/surface/completion_queue.c
@@ -35,10 +35,13 @@
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/surface/event_string.h"
 
-grpc_tracer_flag grpc_trace_operation_failures = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_operation_failures =
+    GRPC_TRACER_INITIALIZER(false, "op_failure");
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_pending_tags = GRPC_TRACER_INITIALIZER(false);
-grpc_tracer_flag grpc_trace_cq_refcount = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_pending_tags =
+    GRPC_TRACER_INITIALIZER(false, "pending_tags");
+grpc_tracer_flag grpc_trace_cq_refcount =
+    GRPC_TRACER_INITIALIZER(false, "cq_refcount");
 #endif
 
 typedef struct {
@@ -343,8 +346,10 @@ static const cq_vtable g_cq_vtable[] = {
 #define POLLSET_FROM_CQ(cq) \
   ((grpc_pollset *)(cq->vtable->data_size + (char *)DATA_FROM_CQ(cq)))
 
-grpc_tracer_flag grpc_cq_pluck_trace = GRPC_TRACER_INITIALIZER(true);
-grpc_tracer_flag grpc_cq_event_timeout_trace = GRPC_TRACER_INITIALIZER(true);
+grpc_tracer_flag grpc_cq_pluck_trace =
+    GRPC_TRACER_INITIALIZER(true, "queue_pluck");
+grpc_tracer_flag grpc_cq_event_timeout_trace =
+    GRPC_TRACER_INITIALIZER(true, "queue_timeout");
 
 #define GRPC_SURFACE_TRACE_RETURNED_EVENT(cq, event)    \
   if (GRPC_TRACER_ON(grpc_api_trace) &&                 \
diff --git a/src/core/lib/surface/init.c b/src/core/lib/surface/init.c
index 14a86bfa0a..db111e597f 100644
--- a/src/core/lib/surface/init.c
+++ b/src/core/lib/surface/init.c
@@ -120,29 +120,27 @@ void grpc_init(void) {
     grpc_slice_intern_init();
     grpc_mdctx_global_init();
     grpc_channel_init_init();
-    grpc_register_tracer("api", &grpc_api_trace);
-    grpc_register_tracer("channel", &grpc_trace_channel);
-    grpc_register_tracer("connectivity_state", &grpc_connectivity_state_trace);
-    grpc_register_tracer("channel_stack_builder",
-                         &grpc_trace_channel_stack_builder);
-    grpc_register_tracer("http1", &grpc_http1_trace);
-    grpc_register_tracer("queue_pluck", &grpc_cq_pluck_trace);  // default on
-    grpc_register_tracer("combiner", &grpc_combiner_trace);
-    grpc_register_tracer("server_channel", &grpc_server_channel_trace);
-    grpc_register_tracer("bdp_estimator", &grpc_bdp_estimator_trace);
-    grpc_register_tracer("queue_timeout",
-                         &grpc_cq_event_timeout_trace);  // default on
-    grpc_register_tracer("op_failure", &grpc_trace_operation_failures);
-    grpc_register_tracer("resource_quota", &grpc_resource_quota_trace);
-    grpc_register_tracer("call_error", &grpc_call_error_trace);
+    grpc_register_tracer(&grpc_api_trace);
+    grpc_register_tracer(&grpc_trace_channel);
+    grpc_register_tracer(&grpc_connectivity_state_trace);
+    grpc_register_tracer(&grpc_trace_channel_stack_builder);
+    grpc_register_tracer(&grpc_http1_trace);
+    grpc_register_tracer(&grpc_cq_pluck_trace);  // default on
+    grpc_register_tracer(&grpc_combiner_trace);
+    grpc_register_tracer(&grpc_server_channel_trace);
+    grpc_register_tracer(&grpc_bdp_estimator_trace);
+    grpc_register_tracer(&grpc_cq_event_timeout_trace);  // default on
+    grpc_register_tracer(&grpc_trace_operation_failures);
+    grpc_register_tracer(&grpc_resource_quota_trace);
+    grpc_register_tracer(&grpc_call_error_trace);
 #ifndef NDEBUG
-    grpc_register_tracer("pending_tags", &grpc_trace_pending_tags);
-    grpc_register_tracer("queue_refcount", &grpc_trace_cq_refcount);
-    grpc_register_tracer("closure", &grpc_trace_closure);
-    grpc_register_tracer("error_refcount", &grpc_trace_error_refcount);
-    grpc_register_tracer("stream_refcount", &grpc_trace_stream_refcount);
-    grpc_register_tracer("fd_refcount", &grpc_trace_fd_refcount);
-    grpc_register_tracer("metadata", &grpc_trace_metadata);
+    grpc_register_tracer(&grpc_trace_pending_tags);
+    grpc_register_tracer(&grpc_trace_cq_refcount);
+    grpc_register_tracer(&grpc_trace_closure);
+    grpc_register_tracer(&grpc_trace_error_refcount);
+    grpc_register_tracer(&grpc_trace_stream_refcount);
+    grpc_register_tracer(&grpc_trace_fd_refcount);
+    grpc_register_tracer(&grpc_trace_metadata);
 #endif
     grpc_security_pre_init();
     grpc_iomgr_init(&exec_ctx);
diff --git a/src/core/lib/surface/init_secure.c b/src/core/lib/surface/init_secure.c
index 7dbea581d0..2366c24910 100644
--- a/src/core/lib/surface/init_secure.c
+++ b/src/core/lib/surface/init_secure.c
@@ -37,13 +37,11 @@
 #endif
 
 void grpc_security_pre_init(void) {
-  grpc_register_tracer("secure_endpoint", &grpc_trace_secure_endpoint);
-  grpc_register_tracer("transport_security", &tsi_tracing_enabled);
+  grpc_register_tracer(&grpc_trace_secure_endpoint);
+  grpc_register_tracer(&tsi_tracing_enabled);
 #ifndef NDEBUG
-  grpc_register_tracer("auth_context_refcount",
-                       &grpc_trace_auth_context_refcount);
-  grpc_register_tracer("security_connector_refcount",
-                       &grpc_trace_security_connector_refcount);
+  grpc_register_tracer(&grpc_trace_auth_context_refcount);
+  grpc_register_tracer(&grpc_trace_security_connector_refcount);
 #endif
 }
 
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index de0a91e2b2..fce7f8dca1 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -58,7 +58,8 @@ typedef struct registered_method registered_method;
 
 typedef enum { BATCH_CALL, REGISTERED_CALL } requested_call_type;
 
-grpc_tracer_flag grpc_server_channel_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_server_channel_trace =
+    GRPC_TRACER_INITIALIZER(false, "server_channel");
 
 typedef struct requested_call {
   requested_call_type type;
diff --git a/src/core/lib/transport/bdp_estimator.c b/src/core/lib/transport/bdp_estimator.c
index d33e3a48ab..311ae6390d 100644
--- a/src/core/lib/transport/bdp_estimator.c
+++ b/src/core/lib/transport/bdp_estimator.c
@@ -23,7 +23,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/useful.h>
 
-grpc_tracer_flag grpc_bdp_estimator_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_bdp_estimator_trace =
+    GRPC_TRACER_INITIALIZER(false, "bdp_estimator");
 
 void grpc_bdp_estimator_init(grpc_bdp_estimator *estimator, const char *name) {
   estimator->estimate = 65536;
diff --git a/src/core/lib/transport/connectivity_state.c b/src/core/lib/transport/connectivity_state.c
index 6fe40af3b2..73a9178ae2 100644
--- a/src/core/lib/transport/connectivity_state.c
+++ b/src/core/lib/transport/connectivity_state.c
@@ -24,7 +24,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-grpc_tracer_flag grpc_connectivity_state_trace = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_connectivity_state_trace =
+    GRPC_TRACER_INITIALIZER(false, "connectivity_state");
 
 const char *grpc_connectivity_state_name(grpc_connectivity_state state) {
   switch (state) {
diff --git a/src/core/lib/transport/metadata.c b/src/core/lib/transport/metadata.c
index 87a2abf344..2fea366072 100644
--- a/src/core/lib/transport/metadata.c
+++ b/src/core/lib/transport/metadata.c
@@ -48,7 +48,8 @@
  */
 
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_metadata = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_metadata =
+    GRPC_TRACER_INITIALIZER(false, "metadata");
 #define DEBUG_ARGS , const char *file, int line
 #define FWD_DEBUG_ARGS , file, line
 #define REF_MD_LOCKED(shard, s) ref_md_locked((shard), (s), __FILE__, __LINE__)
diff --git a/src/core/lib/transport/transport.c b/src/core/lib/transport/transport.c
index 6a9eba110d..7281602d66 100644
--- a/src/core/lib/transport/transport.c
+++ b/src/core/lib/transport/transport.c
@@ -32,7 +32,8 @@
 #include "src/core/lib/transport/transport_impl.h"
 
 #ifndef NDEBUG
-grpc_tracer_flag grpc_trace_stream_refcount = GRPC_TRACER_INITIALIZER(false);
+grpc_tracer_flag grpc_trace_stream_refcount =
+    GRPC_TRACER_INITIALIZER(false, "stream_refcount");
 #endif
 
 #ifndef NDEBUG