Use atomic time pair for g_start_time
diff --git a/src/core/lib/iomgr/exec_ctx.cc b/src/core/lib/iomgr/exec_ctx.cc
index 79ce33f..c3182dc 100644
--- a/src/core/lib/iomgr/exec_ctx.cc
+++ b/src/core/lib/iomgr/exec_ctx.cc
@@ -107,27 +107,43 @@
grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
}
-static gpr_timespec
+typedef struct time_atm_pair {
+ gpr_atm tv_sec;
+ gpr_atm tv_nsec;
+} time_atm_pair;
+
+static time_atm_pair
g_start_time[GPR_TIMESPAN + 1]; // assumes GPR_TIMESPAN is the
// last enum value in
// gpr_clock_type
-
static grpc_millis g_last_start_time_update;
-static gpr_mu g_start_time_mu;
+
+static gpr_timespec timespec_from_time_atm_pair(const time_atm_pair* src, gpr_clock_type clock_type) {
+ gpr_timespec time;
+ time.tv_nsec = (int32_t)gpr_atm_no_barrier_load(&src->tv_nsec);
+ time.tv_sec = (int64_t)gpr_atm_no_barrier_load(&src->tv_sec);
+ time.clock_type = clock_type;
+ return time;
+}
+
+static void time_atm_pair_store(time_atm_pair* dst, const gpr_timespec src) {
+ gpr_atm_no_barrier_store(&dst->tv_sec, src.tv_sec);
+ gpr_atm_no_barrier_store(&dst->tv_nsec, src.tv_nsec);
+}
void grpc_exec_ctx_global_init(void) {
for (int i = 0; i < GPR_TIMESPAN; i++) {
- g_start_time[i] = gpr_now((gpr_clock_type)i);
+ time_atm_pair_store(&g_start_time[i], gpr_now((gpr_clock_type)i));
}
// allows uniform treatment in conversion functions
- g_start_time[GPR_TIMESPAN] = gpr_time_0(GPR_TIMESPAN);
- gpr_mu_init(&g_start_time_mu);
+ time_atm_pair_store(&g_start_time[GPR_TIMESPAN], gpr_time_0(GPR_TIMESPAN));
}
void grpc_exec_ctx_global_shutdown(void) {}
static gpr_atm timespec_to_atm_round_down(gpr_timespec ts) {
- ts = gpr_time_sub(ts, g_start_time[ts.clock_type]);
+ gpr_timespec start_time = timespec_from_time_atm_pair(&g_start_time[ts.clock_type], ts.clock_type);
+ ts = gpr_time_sub(ts, start_time);
double x =
GPR_MS_PER_SEC * (double)ts.tv_sec + (double)ts.tv_nsec / GPR_NS_PER_MS;
if (x < 0) return 0;
@@ -136,7 +152,8 @@
}
static gpr_atm timespec_to_atm_round_up(gpr_timespec ts) {
- ts = gpr_time_sub(ts, g_start_time[ts.clock_type]);
+ gpr_timespec start_time = timespec_from_time_atm_pair(&g_start_time[ts.clock_type], ts.clock_type);
+ ts = gpr_time_sub(ts, start_time);
double x = GPR_MS_PER_SEC * (double)ts.tv_sec +
(double)ts.tv_nsec / GPR_NS_PER_MS +
(double)(GPR_NS_PER_SEC - 1) / (double)GPR_NS_PER_SEC;
@@ -171,7 +188,8 @@
if (clock_type == GPR_TIMESPAN) {
return gpr_time_from_millis(millis, GPR_TIMESPAN);
}
- return gpr_time_add(g_start_time[clock_type],
+ gpr_timespec start_time = timespec_from_time_atm_pair(&g_start_time[clock_type], clock_type);
+ return gpr_time_add(start_time,
gpr_time_from_millis(millis, GPR_TIMESPAN));
}
@@ -185,21 +203,17 @@
void grpc_exec_ctx_maybe_update_start_time(grpc_exec_ctx* exec_ctx) {
grpc_millis now = grpc_exec_ctx_now(exec_ctx);
- grpc_millis last_start_time_update = gpr_atm_acq_load(&g_last_start_time_update);
+ grpc_millis last_start_time_update = gpr_atm_no_barrier_load(&g_last_start_time_update);
if (now > last_start_time_update &&
now - last_start_time_update > GRPC_START_TIME_UPDATE_INTERVAL) {
+ gpr_atm_no_barrier_store(&g_last_start_time_update, now);
gpr_timespec real_now = gpr_now(GPR_CLOCK_REALTIME);
- gpr_timespec old_now = grpc_millis_to_timespec(now, GPR_CLOCK_REALTIME);
- gpr_timespec diff = gpr_time_sub(real_now, old_now);
+ gpr_timespec real_start_time = gpr_time_sub(real_now, gpr_time_from_millis(now, GPR_TIMESPAN));
+ time_atm_pair_store(&g_start_time[GPR_CLOCK_REALTIME], real_start_time);
+
if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
- gpr_log(GPR_DEBUG, "Update start time with diff: %" PRId64 "s %dns", diff.tv_sec, diff.tv_nsec);
+ gpr_log(GPR_DEBUG, "Update realtime clock start time: %" PRId64 "s %dns", real_start_time.tv_sec, real_start_time.tv_nsec);
}
- gpr_mu_lock(&g_start_time_mu);
- if (last_start_time_update == gpr_atm_acq_load(&g_last_start_time_update)) {
- g_start_time[GPR_CLOCK_REALTIME] = gpr_time_add(g_start_time[GPR_CLOCK_REALTIME], diff);
- g_last_start_time_update = now;
- }
- gpr_mu_unlock(&g_start_time_mu);
}
}