From 6487aac5977cf470bc6a2cd0964da2850ee38717 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Thu, 30 Oct 2014 23:57:01 +0100 Subject: Introduce a new time API The old time API is based on erlang:now/0. The major issue with erlang:now/0 is that it was intended to be used for so many unrelated things. This tied these unrelated operations together and unnecessarily caused performance, scalability as well as accuracy, and precision issues for operations that do not need to have such issues. The new API spreads different functionality over multiple functions in order to improve on this. The new API consists of a number of new BIFs: - erlang:convert_time_unit/3 - erlang:monotonic_time/0 - erlang:monotonic_time/1 - erlang:system_time/0 - erlang:system_time/1 - erlang:time_offset/0 - erlang:time_offset/1 - erlang:timestamp/0 - erlang:unique_integer/0 - erlang:unique_integer/1 - os:system_time/0 - os:system_time/1 and a number of extensions of existing BIFs: - erlang:monitor(time_offset, clock_service) - erlang:system_flag(time_offset, finalize) - erlang:system_info(os_monotonic_time_source) - erlang:system_info(time_offset) - erlang:system_info(time_warp_mode) - erlang:system_info(time_correction) - erlang:system_info(start_time) See the "Time and Time Correction in Erlang" chapter of the ERTS User's Guide for more information. --- erts/emulator/sys/common/erl_poll.c | 221 ++++++++++++++++++++++++++++-------- 1 file changed, 171 insertions(+), 50 deletions(-) (limited to 'erts/emulator/sys/common/erl_poll.c') diff --git a/erts/emulator/sys/common/erl_poll.c b/erts/emulator/sys/common/erl_poll.c index aa412a20c8..f4d4a85ca4 100644 --- a/erts/emulator/sys/common/erl_poll.c +++ b/erts/emulator/sys/common/erl_poll.c @@ -320,7 +320,7 @@ struct ErtsPollSet_ { #if defined(USE_THREADS) || ERTS_POLL_ASYNC_INTERRUPT_SUPPORT erts_atomic32_t wakeup_state; #endif - erts_smp_atomic32_t timeout; + erts_atomic64_t timeout_time; #ifdef ERTS_POLL_COUNT_AVOIDED_WAKEUPS erts_smp_atomic_t no_avoided_wakeups; erts_smp_atomic_t no_avoided_interrupts; @@ -384,6 +384,26 @@ static void check_poll_status(ErtsPollSet ps); static void print_misc_debug_info(void); #endif +static ERTS_INLINE void +init_timeout_time(ErtsPollSet ps) +{ + erts_atomic64_init_nob(&ps->timeout_time, + (erts_aint64_t) ERTS_MONOTONIC_TIME_MAX); +} + +static ERTS_INLINE void +set_timeout_time(ErtsPollSet ps, ErtsMonotonicTime time) +{ + erts_atomic64_set_relb(&ps->timeout_time, + (erts_aint64_t) time); +} + +static ERTS_INLINE ErtsMonotonicTime +get_timeout_time(ErtsPollSet ps) +{ + return (ErtsMonotonicTime) erts_atomic64_read_acqb(&ps->timeout_time); +} + #define ERTS_POLL_NOT_WOKEN 0 #define ERTS_POLL_WOKEN -1 #define ERTS_POLL_WOKEN_INTR 1 @@ -1993,44 +2013,153 @@ save_poll_result(ErtsPollSet ps, ErtsPollResFd pr[], int max_res, } } +static ERTS_INLINE ErtsMonotonicTime +get_timeout(ErtsPollSet ps, + int resolution, + ErtsMonotonicTime timeout_time) +{ + ErtsMonotonicTime timeout, save_timeout_time; + + if (timeout_time == ERTS_POLL_NO_TIMEOUT) { + save_timeout_time = ERTS_MONOTONIC_TIME_MIN; + timeout = 0; + } + else { + ErtsMonotonicTime diff_time, current_time; + current_time = erts_get_monotonic_time(); + diff_time = timeout_time - current_time; + if (diff_time <= 0) { + save_timeout_time = ERTS_MONOTONIC_TIME_MIN; + timeout = 0; + } + else { + save_timeout_time = current_time; + switch (resolution) { + case 1000: + /* Round up to nearest even milli second */ + timeout = ERTS_MONOTONIC_TO_MSEC(diff_time - 1) + 1; + if (timeout > (ErtsMonotonicTime) INT_MAX) + timeout = (ErtsMonotonicTime) INT_MAX; + save_timeout_time += ERTS_MSEC_TO_MONOTONIC(timeout); + break; + case 1000000: + /* Round up to nearest even micro second */ + timeout = ERTS_MONOTONIC_TO_USEC(diff_time - 1) + 1; + save_timeout_time += ERTS_USEC_TO_MONOTONIC(timeout); + break; + case 1000000000: + /* Round up to nearest even nano second */ + timeout = ERTS_MONOTONIC_TO_NSEC(diff_time - 1) + 1; + save_timeout_time += ERTS_NSEC_TO_MONOTONIC(timeout); + break; + default: + ERTS_INTERNAL_ERROR("Invalid resolution"); + timeout = 0; + save_timeout_time = 0; + break; + } + } + } + set_timeout_time(ps, save_timeout_time); + return timeout; +} + +#if ERTS_POLL_USE_SELECT + static ERTS_INLINE int -check_fd_events(ErtsPollSet ps, SysTimeval *tv, int max_res) +get_timeout_timeval(ErtsPollSet ps, + SysTimeval *tvp, + ErtsMonotonicTime timeout_time) +{ + ErtsMonotonicTime timeout = get_timeout(ps, + 1000*1000, + timeout_time); + + if (!timeout) { + tvp->tv_sec = 0; + tvp->tv_usec = 0; + + return 0; + } + else { + ErtsMonotonicTime sec = timeout/(1000*1000); + tvp->tv_sec = sec; + tvp->tv_usec = timeout - sec*(1000*1000); + + ASSERT(tvp->tv_sec >= 0); + ASSERT(tvp->tv_usec >= 0); + ASSERT(tvp->tv_usec < 1000*1000); + + return !0; + } + +} + +#endif + +#if ERTS_POLL_USE_KQUEUE + +static ERTS_INLINE int +get_timeout_timespec(ErtsPollSet ps, + struct timespec *tsp, + ErtsMonotonicTime timeout_time) +{ + ErtsMonotonicTime timeout = get_timeout(ps, + 1000*1000*1000, + timeout_time); + + if (!timeout) { + tsp->tv_sec = 0; + tsp->tv_nsec = 0; + return 0; + } + else { + ErtsMonotonicTime sec = timeout/(1000*1000*1000); + tsp->tv_sec = sec; + tsp->tv_nsec = timeout - sec*(1000*1000*1000); + + ASSERT(tsp->tv_sec >= 0); + ASSERT(tsp->tv_nsec >= 0); + ASSERT(tsp->tv_nsec < 1000*1000); + + return !0; + } +} + +#endif + +static ERTS_INLINE int +check_fd_events(ErtsPollSet ps, ErtsMonotonicTime timeout_time, int max_res) { int res; if (erts_smp_atomic_read_nob(&ps->no_of_user_fds) == 0 - && tv->tv_usec == 0 && tv->tv_sec == 0) { + && timeout_time == ERTS_POLL_NO_TIMEOUT) { /* Nothing to poll and zero timeout; done... */ return 0; } else { - long timeout = tv->tv_sec*1000 + tv->tv_usec/1000; - if (timeout > ERTS_AINT32_T_MAX) - timeout = ERTS_AINT32_T_MAX; - ASSERT(timeout >= 0); - erts_smp_atomic32_set_relb(&ps->timeout, (erts_aint32_t) timeout); + int timeout; #if ERTS_POLL_USE_FALLBACK if (!(ps->fallback_used = ERTS_POLL_NEED_FALLBACK(ps))) { #if ERTS_POLL_USE_EPOLL /* --- epoll ------------------------------- */ - if (timeout > INT_MAX) - timeout = INT_MAX; if (max_res > ps->res_events_len) grow_res_events(ps, max_res); + timeout = (int) get_timeout(ps, 1000, timeout_time); #ifdef ERTS_SMP if (timeout) erts_thr_progress_prepare_wait(NULL); #endif - res = epoll_wait(ps->kp_fd, ps->res_events, max_res, (int)timeout); + res = epoll_wait(ps->kp_fd, ps->res_events, max_res, timeout); #elif ERTS_POLL_USE_KQUEUE /* --- kqueue ------------------------------ */ struct timespec ts; if (max_res > ps->res_events_len) grow_res_events(ps, max_res); + timeout = get_timeout_timespec(ps, &ts, timeout_time); #ifdef ERTS_SMP if (timeout) erts_thr_progress_prepare_wait(NULL); #endif - ts.tv_sec = tv->tv_sec; - ts.tv_nsec = tv->tv_usec*1000; res = kevent(ps->kp_fd, NULL, 0, ps->res_events, max_res, &ts); #endif /* ----------------------------------------- */ } @@ -2049,8 +2178,7 @@ check_fd_events(ErtsPollSet ps, SysTimeval *tv, int max_res) #if ERTS_POLL_USE_WAKEUP_PIPE nfds++; /* Wakeup pipe */ #endif - if (timeout > INT_MAX) - timeout = INT_MAX; + timeout = (int) get_timeout(ps, 1000, timeout_time); poll_res.dp_nfds = nfds < max_res ? nfds : max_res; if (poll_res.dp_nfds > ps->res_events_len) grow_res_events(ps, poll_res.dp_nfds); @@ -2059,33 +2187,33 @@ check_fd_events(ErtsPollSet ps, SysTimeval *tv, int max_res) if (timeout) erts_thr_progress_prepare_wait(NULL); #endif - poll_res.dp_timeout = (int) timeout; + poll_res.dp_timeout = timeout; res = ioctl(ps->kp_fd, DP_POLL, &poll_res); #elif ERTS_POLL_USE_POLL /* --- poll -------------------------------- */ - if (timeout > INT_MAX) - timeout = INT_MAX; + timeout = (int) get_timeout(ps, 1000, timeout_time); #ifdef ERTS_SMP if (timeout) erts_thr_progress_prepare_wait(NULL); #endif - res = poll(ps->poll_fds, ps->no_poll_fds, (int) timeout); + res = poll(ps->poll_fds, ps->no_poll_fds, timeout); #elif ERTS_POLL_USE_SELECT /* --- select ------------------------------ */ - SysTimeval to = *tv; + SysTimeval to; + timeout = get_timeout_timeval(ps, &to, timeout_time); ERTS_FD_COPY(&ps->input_fds, &ps->res_input_fds); ERTS_FD_COPY(&ps->output_fds, &ps->res_output_fds); #ifdef ERTS_SMP - if (to.tv_sec || to.tv_usec) + if (timeout) erts_thr_progress_prepare_wait(NULL); #endif res = ERTS_SELECT(ps->max_fd + 1, - &ps->res_input_fds, - &ps->res_output_fds, - NULL, - &to); + &ps->res_input_fds, + &ps->res_output_fds, + NULL, + &to); #ifdef ERTS_SMP - if (to.tv_sec || to.tv_usec) + if (timeout) erts_thr_progress_finalize_wait(NULL); if (res < 0 && errno == EBADF @@ -2108,10 +2236,10 @@ check_fd_events(ErtsPollSet ps, SysTimeval *tv, int max_res) handle_update_requests(ps); ERTS_POLLSET_UNLOCK(ps); res = ERTS_SELECT(ps->max_fd + 1, - &ps->res_input_fds, - &ps->res_output_fds, - NULL, - &to); + &ps->res_input_fds, + &ps->res_output_fds, + NULL, + &to); if (res == 0) { errno = EAGAIN; res = -1; @@ -2133,15 +2261,14 @@ int ERTS_POLL_EXPORT(erts_poll_wait)(ErtsPollSet ps, ErtsPollResFd pr[], int *len, - SysTimeval *utvp) + ErtsMonotonicTime timeout_time) { + ErtsMonotonicTime to; int res, no_fds; int ebadf = 0; #ifdef ERTS_SMP int ps_locked = 0; #endif - SysTimeval *tvp; - SysTimeval itv; no_fds = *len; #ifdef ERTS_POLL_MAX_RES @@ -2151,13 +2278,9 @@ ERTS_POLL_EXPORT(erts_poll_wait)(ErtsPollSet ps, *len = 0; - ASSERT(utvp); - - tvp = utvp; - #ifdef ERTS_POLL_DEBUG_PRINT - erts_printf("Entering erts_poll_wait(), timeout=%d\n", - (int) tvp->tv_sec*1000 + tvp->tv_usec/1000); + erts_printf("Entering erts_poll_wait(), timeout_time=%bps\n", + timeout_time); #endif if (ERTS_POLLSET_SET_POLLED_CHK(ps)) { @@ -2166,12 +2289,9 @@ ERTS_POLL_EXPORT(erts_poll_wait)(ErtsPollSet ps, goto done; } - if (is_woken(ps)) { - /* Use zero timeout */ - itv.tv_sec = 0; - itv.tv_usec = 0; - tvp = &itv; - } + to = (is_woken(ps) + ? ERTS_POLL_NO_TIMEOUT /* Use zero timeout */ + : timeout_time); #if ERTS_POLL_USE_UPDATE_REQUESTS_QUEUE if (ERTS_POLLSET_HAVE_UPDATE_REQUESTS(ps)) { @@ -2181,7 +2301,7 @@ ERTS_POLL_EXPORT(erts_poll_wait)(ErtsPollSet ps, } #endif - res = check_fd_events(ps, tvp, no_fds); + res = check_fd_events(ps, to, no_fds); woke_up(ps); @@ -2224,7 +2344,7 @@ ERTS_POLL_EXPORT(erts_poll_wait)(ErtsPollSet ps, #endif done: - erts_smp_atomic32_set_relb(&ps->timeout, ERTS_AINT32_T_MAX); + set_timeout_time(ps, ERTS_MONOTONIC_TIME_MAX); #ifdef ERTS_POLL_DEBUG_PRINT erts_printf("Leaving %s = erts_poll_wait()\n", res == 0 ? "0" : erl_errno_id(res)); @@ -2268,13 +2388,14 @@ ERTS_POLL_EXPORT(erts_poll_async_sig_interrupt)(ErtsPollSet ps) void ERTS_POLL_EXPORT(erts_poll_interrupt_timed)(ErtsPollSet ps, int set, - erts_short_time_t msec) + ErtsMonotonicTime timeout_time) { #if ERTS_POLL_ASYNC_INTERRUPT_SUPPORT || defined(ERTS_SMP) if (!set) reset_wakeup_state(ps); else { - if (erts_smp_atomic32_read_acqb(&ps->timeout) > (erts_aint32_t) msec) + ErtsMonotonicTime max_wait_time = get_timeout_time(ps); + if (max_wait_time > timeout_time) wake_poller(ps, 1, 0); #ifdef ERTS_POLL_COUNT_AVOIDED_WAKEUPS else { @@ -2431,7 +2552,7 @@ ERTS_POLL_EXPORT(erts_poll_create_pollset)(void) ps->internal_fd_limit = kp_fd + 1; ps->kp_fd = kp_fd; #endif - erts_smp_atomic32_init_nob(&ps->timeout, ERTS_AINT32_T_MAX); + init_timeout_time(ps); #ifdef ERTS_POLL_COUNT_AVOIDED_WAKEUPS erts_smp_atomic_init_nob(&ps->no_avoided_wakeups, 0); erts_smp_atomic_init_nob(&ps->no_avoided_interrupts, 0); -- cgit v1.2.3