X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;ds=sidebyside;f=lib%2Ftimeval.c;h=05da99e5670395d790c9d1a34b0559560031bc48;hb=d017eeb9f9ebcb46c24a67fd301b3e36cd26a04e;hp=77247e80ac71583c9690522bf7e9153bfdfc7d26;hpb=a457574880b01a30c16e9b92c9ead760631de3c1;p=sliver-openvswitch.git diff --git a/lib/timeval.c b/lib/timeval.c index 77247e80a..05da99e56 100644 --- a/lib/timeval.c +++ b/lib/timeval.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc. + * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -16,9 +16,9 @@ #include #include "timeval.h" -#include #include #include +#include #include #include #include @@ -27,7 +27,11 @@ #include #include "coverage.h" #include "dummy.h" +#include "dynamic-string.h" #include "fatal-signal.h" +#include "hash.h" +#include "hmap.h" +#include "ovs-thread.h" #include "signals.h" #include "unixctl.h" #include "util.h" @@ -35,45 +39,37 @@ VLOG_DEFINE_THIS_MODULE(timeval); -/* The clock to use for measuring time intervals. This is CLOCK_MONOTONIC by - * preference, but on systems that don't have a monotonic clock we fall back - * to CLOCK_REALTIME. */ -static clockid_t monotonic_clock; +struct clock { + clockid_t id; /* CLOCK_MONOTONIC or CLOCK_REALTIME. */ + struct ovs_rwlock rwlock; /* Mutual exclusion for 'cache'. */ -/* Controls whether or not calls to clock_gettime() are cached. See - * time_cached() for a detailed explanation. */ -#if defined __x86_64__ && defined __linux__ -static bool cache_time = false; -#else -static bool cache_time = true; -#endif + /* Features for use by unit tests. Protected by 'rwlock'. */ + struct timespec warp; /* Offset added for unit tests. */ + bool stopped; /* Disables real-time updates if true. */ -/* Has a timer tick occurred? Only relevant if cache_time is true. - * - * We initialize these to true to force time_init() to get called on the first - * call to time_msec() or another function that queries the current time. */ -static volatile sig_atomic_t wall_tick = true; -static volatile sig_atomic_t monotonic_tick = true; + /* Relevant only if CACHE_TIME is true. */ + volatile sig_atomic_t tick; /* Has the timer ticked? Set by signal. */ + struct timespec cache; /* Last time read from kernel. */ +}; -/* The current time, as of the last refresh. */ -static struct timespec wall_time; -static struct timespec monotonic_time; +/* Our clocks. */ +static struct clock monotonic_clock; /* CLOCK_MONOTONIC, if available. */ +static struct clock wall_clock; /* CLOCK_REALTIME. */ /* The monotonic time at which the time module was initialized. */ static long long int boot_time; -/* features for use by unit tests. */ -static struct timespec warp_offset; /* Offset added to monotonic_time. */ -static bool time_stopped; /* Disables real-time updates, if true. */ - -/* Time in milliseconds at which to die with SIGALRM (if not LLONG_MAX). */ +/* Monotonic time in milliseconds at which to die with SIGALRM (if not + * LLONG_MAX). */ static long long int deadline = LLONG_MAX; +/* Monotonic time, in milliseconds, at which the last call to time_poll() woke + * up. */ +DEFINE_PER_THREAD_DATA(long long int, last_wakeup, 0); + static void set_up_timer(void); static void set_up_signal(int flags); static void sigalrm_handler(int); -static void refresh_wall_if_ticked(void); -static void refresh_monotonic_if_ticked(void); static void block_sigalrm(sigset_t *); static void unblock_sigalrm(const sigset_t *); static void log_poll_interval(long long int last_wakeup); @@ -82,29 +78,38 @@ static void refresh_rusage(void); static void timespec_add(struct timespec *sum, const struct timespec *a, const struct timespec *b); -/* Initializes the timetracking module, if not already initialized. */ static void -time_init(void) +init_clock(struct clock *c, clockid_t id) { - static bool inited; - if (inited) { - return; - } - inited = true; + memset(c, 0, sizeof *c); + c->id = id; + ovs_rwlock_init(&c->rwlock); + xclock_gettime(c->id, &c->cache); +} + +static void +do_init_time(void) +{ + struct timespec ts; coverage_init(); - if (!clock_gettime(CLOCK_MONOTONIC, &monotonic_time)) { - monotonic_clock = CLOCK_MONOTONIC; - } else { - monotonic_clock = CLOCK_REALTIME; - VLOG_DBG("monotonic timer not available"); - } + init_clock(&monotonic_clock, (!clock_gettime(CLOCK_MONOTONIC, &ts) + ? CLOCK_MONOTONIC + : CLOCK_REALTIME)); + init_clock(&wall_clock, CLOCK_REALTIME); + boot_time = timespec_to_msec(&monotonic_clock.cache); set_up_signal(SA_RESTART); set_up_timer(); +} - boot_time = time_msec(); +/* Initializes the timetracking module, if not already initialized. */ +static void +time_init(void) +{ + static pthread_once_t once = PTHREAD_ONCE_INIT; + pthread_once(&once, do_init_time); } static void @@ -119,50 +124,18 @@ set_up_signal(int flags) xsigaction(SIGALRM, &sa, NULL); } -/* Remove SA_RESTART from the flags for SIGALRM, so that any system call that - * is interrupted by the periodic timer interrupt will return EINTR instead of - * continuing after the signal handler returns. - * - * time_disable_restart() and time_enable_restart() may be usefully wrapped - * around function calls that might otherwise block forever unless interrupted - * by a signal, e.g.: - * - * time_disable_restart(); - * fcntl(fd, F_SETLKW, &lock); - * time_enable_restart(); - */ -void -time_disable_restart(void) -{ - time_init(); - set_up_signal(0); -} - -/* Add SA_RESTART to the flags for SIGALRM, so that any system call that - * is interrupted by the periodic timer interrupt will continue after the - * signal handler returns instead of returning EINTR. */ -void -time_enable_restart(void) -{ - time_init(); - set_up_signal(SA_RESTART); -} - static void set_up_timer(void) { static timer_t timer_id; /* "static" to avoid apparent memory leak. */ struct itimerspec itimer; - if (!cache_time) { + if (!CACHE_TIME) { return; } - if (timer_create(monotonic_clock, NULL, &timer_id)) { - VLOG_WARN("timer_create failed (%s), disabling cached timing", - strerror(errno)); - cache_time = false; - return; + if (timer_create(monotonic_clock.id, NULL, &timer_id)) { + VLOG_FATAL("timer_create failed (%s)", ovs_strerror(errno)); } itimer.it_interval.tv_sec = 0; @@ -170,7 +143,7 @@ set_up_timer(void) itimer.it_value = itimer.it_interval; if (timer_settime(timer_id, 0, &itimer, NULL)) { - VLOG_FATAL("timer_settime failed (%s)", strerror(errno)); + VLOG_FATAL("timer_settime failed (%s)", ovs_strerror(errno)); } } @@ -182,95 +155,107 @@ set_up_timer(void) void time_postfork(void) { + assert_single_threaded(); time_init(); set_up_timer(); } -static void -refresh_wall(void) +/* Forces a refresh of the current time from the kernel. It is not usually + * necessary to call this function, since the time will be refreshed + * automatically at least every TIME_UPDATE_INTERVAL milliseconds. If + * CACHE_TIME is false, we will always refresh the current time so this + * function has no effect. */ +void +time_refresh(void) { - time_init(); - clock_gettime(CLOCK_REALTIME, &wall_time); - wall_tick = false; + monotonic_clock.tick = wall_clock.tick = true; } static void -refresh_monotonic(void) +time_timespec__(struct clock *c, struct timespec *ts) { time_init(); - - if (!time_stopped) { - if (monotonic_clock == CLOCK_MONOTONIC) { - clock_gettime(monotonic_clock, &monotonic_time); - } else { - refresh_wall_if_ticked(); - monotonic_time = wall_time; + for (;;) { + /* Use the cached time by preference, but fall through if there's been + * a clock tick. */ + ovs_rwlock_rdlock(&c->rwlock); + if (c->stopped || !c->tick) { + timespec_add(ts, &c->cache, &c->warp); + ovs_rwlock_unlock(&c->rwlock); + return; } - timespec_add(&monotonic_time, &monotonic_time, &warp_offset); + ovs_rwlock_unlock(&c->rwlock); - monotonic_tick = false; + /* Refresh the cache. */ + ovs_rwlock_wrlock(&c->rwlock); + if (c->tick) { + c->tick = false; + xclock_gettime(c->id, &c->cache); + } + ovs_rwlock_unlock(&c->rwlock); } } -/* Forces a refresh of the current time from the kernel. It is not usually - * necessary to call this function, since the time will be refreshed - * automatically at least every TIME_UPDATE_INTERVAL milliseconds. If - * cache_time is false, we will always refresh the current time so this - * function has no effect. */ +/* Stores a monotonic timer, accurate within TIME_UPDATE_INTERVAL ms, into + * '*ts'. */ void -time_refresh(void) +time_timespec(struct timespec *ts) +{ + time_timespec__(&monotonic_clock, ts); +} + +/* Stores the current time, accurate within TIME_UPDATE_INTERVAL ms, into + * '*ts'. */ +void +time_wall_timespec(struct timespec *ts) { - wall_tick = monotonic_tick = true; + time_timespec__(&wall_clock, ts); +} + +static time_t +time_sec__(struct clock *c) +{ + struct timespec ts; + + time_timespec__(c, &ts); + return ts.tv_sec; } /* Returns a monotonic timer, in seconds. */ time_t time_now(void) { - refresh_monotonic_if_ticked(); - return monotonic_time.tv_sec; + return time_sec__(&monotonic_clock); } /* Returns the current time, in seconds. */ time_t time_wall(void) { - refresh_wall_if_ticked(); - return wall_time.tv_sec; + return time_sec__(&wall_clock); +} + +static long long int +time_msec__(struct clock *c) +{ + struct timespec ts; + + time_timespec__(c, &ts); + return timespec_to_msec(&ts); } /* Returns a monotonic timer, in ms (within TIME_UPDATE_INTERVAL ms). */ long long int time_msec(void) { - refresh_monotonic_if_ticked(); - return timespec_to_msec(&monotonic_time); + return time_msec__(&monotonic_clock); } /* Returns the current time, in ms (within TIME_UPDATE_INTERVAL ms). */ long long int time_wall_msec(void) { - refresh_wall_if_ticked(); - return timespec_to_msec(&wall_time); -} - -/* Stores a monotonic timer, accurate within TIME_UPDATE_INTERVAL ms, into - * '*ts'. */ -void -time_timespec(struct timespec *ts) -{ - refresh_monotonic_if_ticked(); - *ts = monotonic_time; -} - -/* Stores the current time, accurate within TIME_UPDATE_INTERVAL ms, into - * '*ts'. */ -void -time_wall_timespec(struct timespec *ts) -{ - refresh_wall_if_ticked(); - *ts = wall_time; + return time_msec__(&wall_clock); } /* Configures the program to die with SIGALRM 'secs' seconds from now, if @@ -281,17 +266,13 @@ time_alarm(unsigned int secs) long long int now; long long int msecs; - sigset_t oldsigs; - + assert_single_threaded(); time_init(); time_refresh(); now = time_msec(); - msecs = secs * 1000; - - block_sigalrm(&oldsigs); + msecs = secs * 1000LL; deadline = now < LLONG_MAX - msecs ? now + msecs : LLONG_MAX; - unblock_sigalrm(&oldsigs); } /* Like poll(), except: @@ -312,14 +293,17 @@ int time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, int *elapsed) { - static long long int last_wakeup; + long long int *last_wakeup = last_wakeup_get(); long long int start; sigset_t oldsigs; bool blocked; int retval; + time_init(); time_refresh(); - log_poll_interval(last_wakeup); + if (*last_wakeup) { + log_poll_interval(*last_wakeup); + } coverage_clear(); start = time_msec(); blocked = false; @@ -356,7 +340,7 @@ time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, break; } - if (!blocked && !cache_time) { + if (!blocked && CACHE_TIME) { block_sigalrm(&oldsigs); blocked = true; } @@ -364,50 +348,16 @@ time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, if (blocked) { unblock_sigalrm(&oldsigs); } - last_wakeup = time_msec(); + *last_wakeup = time_msec(); refresh_rusage(); - *elapsed = last_wakeup - start; + *elapsed = *last_wakeup - start; return retval; } -/* True on systems (particularly x86-64 Linux) where clock_gettime() is - * inexpensive. On these systems, we don't bother caching the current time. - * Instead, we consult clock_gettime() directly when needed. - * - * False on systems where clock_gettime() is relatively expensive. On these - * systems, we cache the current time and set up a periodic SIGALRM to remind - * us to update it. - * - * Also false on systems (e.g. ESX) that don't support setting up timers based - * on a monotonically increasing clock. */ -bool -time_cached(void) -{ - time_init(); - return cache_time; -} - static void sigalrm_handler(int sig_nr OVS_UNUSED) { - wall_tick = true; - monotonic_tick = true; -} - -static void -refresh_wall_if_ticked(void) -{ - if (!cache_time || wall_tick) { - refresh_wall(); - } -} - -static void -refresh_monotonic_if_ticked(void) -{ - if (!cache_time || monotonic_tick) { - refresh_monotonic(); - } + monotonic_clock.tick = wall_clock.tick = true; } static void @@ -416,13 +366,13 @@ block_sigalrm(sigset_t *oldsigs) sigset_t sigalrm; sigemptyset(&sigalrm); sigaddset(&sigalrm, SIGALRM); - xsigprocmask(SIG_BLOCK, &sigalrm, oldsigs); + xpthread_sigmask(SIG_BLOCK, &sigalrm, oldsigs); } static void unblock_sigalrm(const sigset_t *oldsigs) { - xsigprocmask(SIG_SETMASK, oldsigs, NULL); + xpthread_sigmask(SIG_SETMASK, oldsigs, NULL); } long long int @@ -438,7 +388,7 @@ timeval_to_msec(const struct timeval *tv) } /* Returns the monotonic time at which the "time" module was initialized, in - * milliseconds(). */ + * milliseconds. */ long long int time_boot_msec(void) { @@ -450,7 +400,17 @@ void xgettimeofday(struct timeval *tv) { if (gettimeofday(tv, NULL) == -1) { - VLOG_FATAL("gettimeofday failed (%s)", strerror(errno)); + VLOG_FATAL("gettimeofday failed (%s)", ovs_strerror(errno)); + } +} + +void +xclock_gettime(clock_t id, struct timespec *ts) +{ + if (clock_gettime(id, ts) == -1) { + /* It seems like a bad idea to try to use vlog here because it is + * likely to try to check the current time. */ + ovs_abort(errno, "xclock_gettime() failed"); } } @@ -480,66 +440,42 @@ timespec_add(struct timespec *sum, static void log_poll_interval(long long int last_wakeup) { - static unsigned int mean_interval; /* In 16ths of a millisecond. */ - static unsigned int n_samples; - - long long int now; - unsigned int interval; /* In 16ths of a millisecond. */ - - /* Compute interval from last wakeup to now in 16ths of a millisecond, - * capped at 10 seconds (16000 in this unit). */ - now = time_msec(); - interval = MIN(10000, now - last_wakeup) << 4; - - /* Warn if we took too much time between polls: at least 50 ms and at least - * 8X the mean interval. */ - if (n_samples > 10 && interval > mean_interval * 8 && interval > 50 * 16) { - static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 3); - - if (!VLOG_DROP_WARN(&rl)) { - const struct rusage *last_rusage = get_recent_rusage(); - struct rusage rusage; - - getrusage(RUSAGE_SELF, &rusage); - VLOG_WARN("%lld ms poll interval (%lld ms user, %lld ms system) " - "is over %u times the weighted mean interval %u ms " - "(%u samples)", - now - last_wakeup, - timeval_diff_msec(&rusage.ru_utime, - &last_rusage->ru_utime), - timeval_diff_msec(&rusage.ru_stime, - &last_rusage->ru_stime), - interval / mean_interval, - (mean_interval + 8) / 16, n_samples); - if (rusage.ru_minflt > last_rusage->ru_minflt - || rusage.ru_majflt > last_rusage->ru_majflt) { - VLOG_WARN("faults: %ld minor, %ld major", - rusage.ru_minflt - last_rusage->ru_minflt, - rusage.ru_majflt - last_rusage->ru_majflt); - } - if (rusage.ru_inblock > last_rusage->ru_inblock - || rusage.ru_oublock > last_rusage->ru_oublock) { - VLOG_WARN("disk: %ld reads, %ld writes", - rusage.ru_inblock - last_rusage->ru_inblock, - rusage.ru_oublock - last_rusage->ru_oublock); - } - if (rusage.ru_nvcsw > last_rusage->ru_nvcsw - || rusage.ru_nivcsw > last_rusage->ru_nivcsw) { - VLOG_WARN("context switches: %ld voluntary, %ld involuntary", - rusage.ru_nvcsw - last_rusage->ru_nvcsw, - rusage.ru_nivcsw - last_rusage->ru_nivcsw); - } + long long int interval = time_msec() - last_wakeup; + + if (interval >= 1000 + && !monotonic_clock.warp.tv_sec + && !monotonic_clock.warp.tv_nsec) { + const struct rusage *last_rusage = get_recent_rusage(); + struct rusage rusage; + + getrusage(RUSAGE_SELF, &rusage); + VLOG_WARN("Unreasonably long %lldms poll interval" + " (%lldms user, %lldms system)", + interval, + timeval_diff_msec(&rusage.ru_utime, + &last_rusage->ru_utime), + timeval_diff_msec(&rusage.ru_stime, + &last_rusage->ru_stime)); + if (rusage.ru_minflt > last_rusage->ru_minflt + || rusage.ru_majflt > last_rusage->ru_majflt) { + VLOG_WARN("faults: %ld minor, %ld major", + rusage.ru_minflt - last_rusage->ru_minflt, + rusage.ru_majflt - last_rusage->ru_majflt); + } + if (rusage.ru_inblock > last_rusage->ru_inblock + || rusage.ru_oublock > last_rusage->ru_oublock) { + VLOG_WARN("disk: %ld reads, %ld writes", + rusage.ru_inblock - last_rusage->ru_inblock, + rusage.ru_oublock - last_rusage->ru_oublock); + } + if (rusage.ru_nvcsw > last_rusage->ru_nvcsw + || rusage.ru_nivcsw > last_rusage->ru_nivcsw) { + VLOG_WARN("context switches: %ld voluntary, %ld involuntary", + rusage.ru_nvcsw - last_rusage->ru_nvcsw, + rusage.ru_nivcsw - last_rusage->ru_nivcsw); } coverage_log(); } - - /* Update exponentially weighted moving average. With these parameters, a - * given value decays to 1% of its value in about 100 time steps. */ - if (n_samples++) { - mean_interval = (mean_interval * 122 + interval * 6 + 64) / 128; - } else { - mean_interval = interval; - } } /* CPU usage tracking. */ @@ -549,37 +485,66 @@ struct cpu_usage { unsigned long long int cpu; /* Total user+system CPU usage when sampled. */ }; -static struct rusage recent_rusage; -static struct cpu_usage older = { LLONG_MIN, 0 }; -static struct cpu_usage newer = { LLONG_MIN, 0 }; -static int cpu_usage = -1; +struct cpu_tracker { + struct cpu_usage older; + struct cpu_usage newer; + int cpu_usage; + + struct rusage recent_rusage; +}; +DEFINE_PER_THREAD_MALLOCED_DATA(struct cpu_tracker *, cpu_tracker_var); + +static struct cpu_tracker * +get_cpu_tracker(void) +{ + struct cpu_tracker *t = cpu_tracker_var_get(); + if (!t) { + t = xzalloc(sizeof *t); + t->older.when = LLONG_MIN; + t->newer.when = LLONG_MIN; + cpu_tracker_var_set_unsafe(t); + } + return t; +} static struct rusage * get_recent_rusage(void) { - return &recent_rusage; + return &get_cpu_tracker()->recent_rusage; +} + +static int +getrusage_thread(struct rusage *rusage OVS_UNUSED) +{ +#ifdef RUSAGE_THREAD + return getrusage(RUSAGE_THREAD, rusage); +#else + errno = EINVAL; + return -1; +#endif } static void refresh_rusage(void) { - long long int now; + struct cpu_tracker *t = get_cpu_tracker(); + struct rusage *recent_rusage = &t->recent_rusage; - now = time_msec(); - getrusage(RUSAGE_SELF, &recent_rusage); - - if (now >= newer.when + 3 * 1000) { - older = newer; - newer.when = now; - newer.cpu = (timeval_to_msec(&recent_rusage.ru_utime) + - timeval_to_msec(&recent_rusage.ru_stime)); - - if (older.when != LLONG_MIN && newer.cpu > older.cpu) { - unsigned int dividend = newer.cpu - older.cpu; - unsigned int divisor = (newer.when - older.when) / 100; - cpu_usage = divisor > 0 ? dividend / divisor : -1; - } else { - cpu_usage = -1; + if (!getrusage_thread(recent_rusage)) { + long long int now = time_msec(); + if (now >= t->newer.when + 3 * 1000) { + t->older = t->newer; + t->newer.when = now; + t->newer.cpu = (timeval_to_msec(&recent_rusage->ru_utime) + + timeval_to_msec(&recent_rusage->ru_stime)); + + if (t->older.when != LLONG_MIN && t->newer.cpu > t->older.cpu) { + unsigned int dividend = t->newer.cpu - t->older.cpu; + unsigned int divisor = (t->newer.when - t->older.when) / 100; + t->cpu_usage = divisor > 0 ? dividend / divisor : -1; + } else { + t->cpu_usage = -1; + } } } } @@ -591,7 +556,7 @@ refresh_rusage(void) int get_cpu_usage(void) { - return cpu_usage; + return get_cpu_tracker()->cpu_usage; } /* Unixctl interface. */ @@ -603,7 +568,10 @@ timeval_stop_cb(struct unixctl_conn *conn, int argc OVS_UNUSED, const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED) { - time_stopped = true; + ovs_rwlock_wrlock(&monotonic_clock.rwlock); + monotonic_clock.stopped = true; + ovs_rwlock_unlock(&monotonic_clock.rwlock); + unixctl_command_reply(conn, NULL); } @@ -627,8 +595,11 @@ timeval_warp_cb(struct unixctl_conn *conn, ts.tv_sec = msecs / 1000; ts.tv_nsec = (msecs % 1000) * 1000 * 1000; - timespec_add(&warp_offset, &warp_offset, &ts); - timespec_add(&monotonic_time, &monotonic_time, &ts); + + ovs_rwlock_wrlock(&monotonic_clock.rwlock); + timespec_add(&monotonic_clock.warp, &monotonic_clock.warp, &ts); + ovs_rwlock_unlock(&monotonic_clock.rwlock); + unixctl_command_reply(conn, "warped"); }