diff options
| -rw-r--r-- | src/core/lib/iomgr/exec_ctx.cc | 70 | ||||
| -rw-r--r-- | src/core/lib/iomgr/exec_ctx.h | 2 | ||||
| -rw-r--r-- | src/core/lib/iomgr/timer_manager.cc | 5 |
3 files changed, 70 insertions, 7 deletions
diff --git a/src/core/lib/iomgr/exec_ctx.cc b/src/core/lib/iomgr/exec_ctx.cc index 0a0ed8a055..423e8d059f 100644 --- a/src/core/lib/iomgr/exec_ctx.cc +++ b/src/core/lib/iomgr/exec_ctx.cc @@ -25,6 +25,9 @@ #include "src/core/lib/iomgr/combiner.h" #include "src/core/lib/profiling/timers.h" +#define GRPC_START_TIME_UPDATE_INTERVAL 10000 +extern "C" grpc_tracer_flag grpc_timer_check_trace; + bool grpc_exec_ctx_ready_to_finish(grpc_exec_ctx* exec_ctx) { if ((exec_ctx->flags & GRPC_EXEC_CTX_FLAG_IS_FINISHED) == 0) { if (exec_ctx->check_ready_to_finish(exec_ctx, @@ -104,23 +107,49 @@ static void exec_ctx_sched(grpc_exec_ctx* exec_ctx, grpc_closure* closure, grpc_closure_list_append(&exec_ctx->closure_list, closure, error); } -static gpr_timespec +/* This time pair is not entirely thread-safe as store/load of tv_sec and + * tv_nsec are performed separately. However g_start_time do not need to have + * sub-second precision, so it is ok if the value of tv_nsec is off in this + * case. */ +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_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); + 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; @@ -129,7 +158,9 @@ static gpr_atm timespec_to_atm_round_down(gpr_timespec ts) { } 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; @@ -164,8 +195,9 @@ gpr_timespec grpc_millis_to_timespec(grpc_millis millis, if (clock_type == GPR_TIMESPAN) { return gpr_time_from_millis(millis, GPR_TIMESPAN); } - return gpr_time_add(g_start_time[clock_type], - gpr_time_from_millis(millis, GPR_TIMESPAN)); + 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)); } grpc_millis grpc_timespec_to_millis_round_down(gpr_timespec ts) { @@ -176,6 +208,30 @@ grpc_millis grpc_timespec_to_millis_round_up(gpr_timespec ts) { return timespec_to_atm_round_up(ts); } +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_no_barrier_load(&g_last_start_time_update); + + if (now > last_start_time_update && + now - last_start_time_update > GRPC_START_TIME_UPDATE_INTERVAL) { + /* Get the current system time and subtract \a now from it, where \a now is + * the relative time from grpc_init() from monotonic clock. This calibrates + * the time when grpc_exec_ctx_global_init was called based on current + * system clock. */ + gpr_atm_no_barrier_store(&g_last_start_time_update, now); + gpr_timespec real_now = gpr_now(GPR_CLOCK_REALTIME); + 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 realtime clock start time: %" PRId64 "s %dns", + real_start_time.tv_sec, real_start_time.tv_nsec); + } + } +} + static const grpc_closure_scheduler_vtable exec_ctx_scheduler_vtable = { exec_ctx_run, exec_ctx_sched, "exec_ctx"}; static grpc_closure_scheduler exec_ctx_scheduler = {&exec_ctx_scheduler_vtable}; diff --git a/src/core/lib/iomgr/exec_ctx.h b/src/core/lib/iomgr/exec_ctx.h index bd27506152..6035e08361 100644 --- a/src/core/lib/iomgr/exec_ctx.h +++ b/src/core/lib/iomgr/exec_ctx.h @@ -124,6 +124,8 @@ gpr_timespec grpc_millis_to_timespec(grpc_millis millis, gpr_clock_type clock); grpc_millis grpc_timespec_to_millis_round_down(gpr_timespec timespec); grpc_millis grpc_timespec_to_millis_round_up(gpr_timespec timespec); +void grpc_exec_ctx_maybe_update_start_time(grpc_exec_ctx* exec_ctx); + #ifdef __cplusplus } #endif diff --git a/src/core/lib/iomgr/timer_manager.cc b/src/core/lib/iomgr/timer_manager.cc index 16e9e7e707..bb2a0e0d44 100644 --- a/src/core/lib/iomgr/timer_manager.cc +++ b/src/core/lib/iomgr/timer_manager.cc @@ -225,6 +225,11 @@ static void timer_main_loop(grpc_exec_ctx* exec_ctx) { for (;;) { grpc_millis next = GRPC_MILLIS_INF_FUTURE; grpc_exec_ctx_invalidate_now(exec_ctx); + + /* Calibrate g_start_time in exec_ctx.cc with a regular interval in case the + * system clock has changed */ + grpc_exec_ctx_maybe_update_start_time(exec_ctx); + // check timer state, updates next to the next time to run a check switch (grpc_timer_check(exec_ctx, &next)) { case GRPC_TIMERS_FIRED: |