Move alarm subsystem to monotonic time

4 files changed, 16 insertions, 10 deletions

diff --git a/src/core/iomgr/alarm.c b/src/core/iomgr/alarm.c
index 5b9a37e5dd..931f746f75 100644
--- a/src/core/iomgr/alarm.c
+++ b/src/core/iomgr/alarm.c
@@ -36,6 +36,7 @@
 #include "src/core/iomgr/alarm_heap.h"
 #include "src/core/iomgr/alarm_internal.h"
 #include "src/core/iomgr/time_averaged_stats.h"
+#include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/useful.h>
 
@@ -67,6 +68,7 @@ typedef struct {
 static gpr_mu g_mu;
 /* Allow only one run_some_expired_alarms at once */
 static gpr_mu g_checker_mu;
+static gpr_clock_type g_clock_type;
 static shard_type g_shards[NUM_SHARDS];
 /* Protected by g_mu */
 static shard_type *g_shard_queue[NUM_SHARDS];
@@ -85,6 +87,7 @@ void grpc_alarm_list_init(gpr_timespec now) {
 
   gpr_mu_init(&g_mu);
   gpr_mu_init(&g_checker_mu);
+  g_clock_type = now.clock_type;
 
   for (i = 0; i < NUM_SHARDS; i++) {
     shard_type *shard = &g_shards[i];
@@ -102,7 +105,7 @@ void grpc_alarm_list_init(gpr_timespec now) {
 
 void grpc_alarm_list_shutdown(void) {
   int i;
-  while (run_some_expired_alarms(NULL, gpr_inf_future(GPR_CLOCK_REALTIME), NULL,
+  while (run_some_expired_alarms(NULL, gpr_inf_future(g_clock_type), NULL,
                                  0))
     ;
   for (i = 0; i < NUM_SHARDS; i++) {
@@ -175,6 +178,8 @@ void grpc_alarm_init(grpc_alarm *alarm, gpr_timespec deadline,
                      gpr_timespec now) {
   int is_first_alarm = 0;
   shard_type *shard = &g_shards[shard_idx(alarm)];
+  GPR_ASSERT(deadline.clock_type == g_clock_type);
+  GPR_ASSERT(now.clock_type == g_clock_type);
   alarm->cb = alarm_cb;
   alarm->cb_arg = alarm_cb_arg;
   alarm->deadline = deadline;
@@ -355,6 +360,7 @@ static int run_some_expired_alarms(gpr_mu *drop_mu, gpr_timespec now,
 }
 
 int grpc_alarm_check(gpr_mu *drop_mu, gpr_timespec now, gpr_timespec *next) {
+  GPR_ASSERT(now.clock_type == g_clock_type);
   return run_some_expired_alarms(drop_mu, now, next, 1);
 }
 
diff --git a/src/core/iomgr/iomgr.c b/src/core/iomgr/iomgr.c
index 0244f689b1..a18c176b30 100644
--- a/src/core/iomgr/iomgr.c
+++ b/src/core/iomgr/iomgr.c
@@ -57,9 +57,9 @@ static grpc_iomgr_object g_root_object;
 static void background_callback_executor(void *ignored) {
   gpr_mu_lock(&g_mu);
   while (!g_shutdown) {
-    gpr_timespec deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
+    gpr_timespec deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
     gpr_timespec short_deadline = gpr_time_add(
-        gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_millis(100, GPR_TIMESPAN));
+        gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_millis(100, GPR_TIMESPAN));
     if (g_cbs_head) {
       grpc_iomgr_closure *closure = g_cbs_head;
       g_cbs_head = closure->next;
@@ -67,7 +67,7 @@ static void background_callback_executor(void *ignored) {
       gpr_mu_unlock(&g_mu);
       closure->cb(closure->cb_arg, closure->success);
       gpr_mu_lock(&g_mu);
-    } else if (grpc_alarm_check(&g_mu, gpr_now(GPR_CLOCK_REALTIME),
+    } else if (grpc_alarm_check(&g_mu, gpr_now(GPR_CLOCK_MONOTONIC),
                                 &deadline)) {
     } else {
       gpr_mu_unlock(&g_mu);
@@ -90,7 +90,7 @@ void grpc_iomgr_init(void) {
   gpr_thd_id id;
   gpr_mu_init(&g_mu);
   gpr_cv_init(&g_rcv);
-  grpc_alarm_list_init(gpr_now(GPR_CLOCK_REALTIME));
+  grpc_alarm_list_init(gpr_now(GPR_CLOCK_MONOTONIC));
   g_root_object.next = g_root_object.prev = &g_root_object;
   g_root_object.name = "root";
   grpc_iomgr_platform_init();
@@ -145,7 +145,7 @@ void grpc_iomgr_shutdown(void) {
       } while (g_cbs_head);
       continue;
     }
-    if (grpc_alarm_check(&g_mu, gpr_inf_future(GPR_CLOCK_REALTIME), NULL)) {
+    if (grpc_alarm_check(&g_mu, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL)) {
       gpr_log(GPR_DEBUG, "got late alarm");
       continue;
     }
diff --git a/src/core/iomgr/pollset_posix.c b/src/core/iomgr/pollset_posix.c
index efb301d81c..c8646af615 100644
--- a/src/core/iomgr/pollset_posix.c
+++ b/src/core/iomgr/pollset_posix.c
@@ -136,7 +136,7 @@ static void finish_shutdown(grpc_pollset *pollset) {
 
 int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
   /* pollset->mu already held */
-  gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
+  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   if (gpr_time_cmp(now, deadline) > 0) {
     return 0;
   }
@@ -205,7 +205,7 @@ int grpc_poll_deadline_to_millis_timeout(gpr_timespec deadline,
                                          gpr_timespec now) {
   gpr_timespec timeout;
   static const int max_spin_polling_us = 10;
-  if (gpr_time_cmp(deadline, gpr_inf_future(GPR_CLOCK_REALTIME)) == 0) {
+  if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
     return -1;
   }
   if (gpr_time_cmp(deadline, gpr_time_add(now, gpr_time_from_micros(
diff --git a/src/core/iomgr/tcp_client_posix.c b/src/core/iomgr/tcp_client_posix.c
index dc0489e64f..1b73e5e1c9 100644
--- a/src/core/iomgr/tcp_client_posix.c
+++ b/src/core/iomgr/tcp_client_posix.c
@@ -253,8 +253,8 @@ void grpc_tcp_client_connect(void (*cb)(void *arg, grpc_endpoint *ep),
   ac->write_closure.cb_arg = ac;
 
   gpr_mu_lock(&ac->mu);
-  grpc_alarm_init(&ac->alarm, deadline, on_alarm, ac,
-                  gpr_now(GPR_CLOCK_REALTIME));
+  grpc_alarm_init(&ac->alarm, gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC), 
+                  on_alarm, ac, gpr_now(GPR_CLOCK_MONOTONIC));
   grpc_fd_notify_on_write(ac->fd, &ac->write_closure);
   gpr_mu_unlock(&ac->mu);