X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Ftimeval.c;h=faf8e7bc8be277b1d3dac0b80d74822ac1f36cb3;hb=fd76a6f94338b668175336434b156827458b5e7d;hp=3c46ed735f8a11fb96032abceb76d05ebacf9fcf;hpb=f54e56fc50259336d447c25929d6a30785c3d468;p=sliver-openvswitch.git diff --git a/lib/timeval.c b/lib/timeval.c index 3c46ed735..faf8e7bc8 100644 --- a/lib/timeval.c +++ b/lib/timeval.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010 Nicira Networks. + * 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. @@ -16,75 +16,102 @@ #include #include "timeval.h" -#include #include #include +#include #include +#include #include #include #include #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" - #include "vlog.h" -#define THIS_MODULE VLM_timeval -/* Initialized? */ -static bool inited; +VLOG_DEFINE_THIS_MODULE(timeval); + +struct clock { + clockid_t id; /* CLOCK_MONOTONIC or CLOCK_REALTIME. */ + struct ovs_rwlock rwlock; /* Mutual exclusion for 'cache'. */ + + /* 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. */ -/* 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; + /* 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. */ +}; -/* Has a timer tick occurred? */ -static volatile sig_atomic_t wall_tick; -static volatile sig_atomic_t monotonic_tick; +/* Our clocks. */ +static struct clock monotonic_clock; /* CLOCK_MONOTONIC, if available. */ +static struct clock wall_clock; /* CLOCK_REALTIME. */ -/* The current time, as of the last refresh. */ -static struct timespec wall_time; -static struct timespec monotonic_time; +/* The monotonic time at which the time module was initialized. */ +static long long int boot_time; -/* Time at which to die with SIGALRM (if not TIME_MIN). */ -static time_t deadline = TIME_MIN; +/* 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_STATIC_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 time_t time_add(time_t, time_t); static void block_sigalrm(sigset_t *); static void unblock_sigalrm(const sigset_t *); -static void log_poll_interval(long long int last_wakeup, - const struct rusage *last_rusage); +static void log_poll_interval(long long int last_wakeup); +static struct rusage *get_recent_rusage(void); +static void refresh_rusage(void); +static void timespec_add(struct timespec *sum, + const struct timespec *a, const struct timespec *b); -/* Initializes the timetracking module. */ -void -time_init(void) +static void +init_clock(struct clock *c, clockid_t id) { - if (inited) { - return; - } + memset(c, 0, sizeof *c); + c->id = id; + ovs_rwlock_init(&c->rwlock); + xclock_gettime(c->id, &c->cache); +} - coverage_init(); +static void +do_init_time(void) +{ + struct timespec ts; - inited = true; - time_refresh(); + 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(); } +/* 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 set_up_signal(int flags) { @@ -94,36 +121,7 @@ set_up_signal(int flags) sa.sa_handler = sigalrm_handler; sigemptyset(&sa.sa_mask); sa.sa_flags = flags; - if (sigaction(SIGALRM, &sa, NULL)) { - ovs_fatal(errno, "sigaction(SIGALRM) failed"); - } -} - -/* 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) -{ - 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) -{ - set_up_signal(SA_RESTART); + xsigaction(SIGALRM, &sa, NULL); } static void @@ -132,8 +130,12 @@ set_up_timer(void) static timer_t timer_id; /* "static" to avoid apparent memory leak. */ struct itimerspec itimer; - if (timer_create(monotonic_clock, NULL, &timer_id)) { - ovs_fatal(errno, "timer_create failed"); + if (!CACHE_TIME) { + 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; @@ -141,7 +143,7 @@ set_up_timer(void) itimer.it_value = itimer.it_interval; if (timer_settime(timer_id, 0, &itimer, NULL)) { - ovs_fatal(errno, "timer_settime failed"); + VLOG_FATAL("timer_settime failed (%s)", ovs_strerror(errno)); } } @@ -153,100 +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) { - 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(); + 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; + } + ovs_rwlock_unlock(&c->rwlock); - if (monotonic_clock == CLOCK_MONOTONIC) { - clock_gettime(monotonic_clock, &monotonic_time); - } else { - refresh_wall_if_ticked(); - monotonic_time = wall_time; + /* 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); } - - monotonic_tick = false; } -/* 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. */ +/* Stores a monotonic timer, accurate within TIME_UPDATE_INTERVAL ms, into + * '*ts'. */ void -time_refresh(void) +time_timespec(struct timespec *ts) { - wall_tick = monotonic_tick = true; + time_timespec__(&monotonic_clock, ts); } -/* Returns a monotonic timer, in seconds. */ -time_t -time_now(void) +/* Stores the current time, accurate within TIME_UPDATE_INTERVAL ms, into + * '*ts'. */ +void +time_wall_timespec(struct timespec *ts) { - refresh_monotonic_if_ticked(); - return monotonic_time.tv_sec; + time_timespec__(&wall_clock, ts); } -/* Same as time_now() except does not write to static variables, for use in - * signal handlers. */ static time_t -time_now_sig(void) +time_sec__(struct clock *c) { - struct timespec cur_time; + struct timespec ts; - clock_gettime(monotonic_clock, &cur_time); - return cur_time.tv_sec; + time_timespec__(c, &ts); + return ts.tv_sec; +} + +/* Returns a monotonic timer, in seconds. */ +time_t +time_now(void) +{ + 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 @@ -254,58 +263,84 @@ time_wall_timespec(struct timespec *ts) void time_alarm(unsigned int secs) { - sigset_t oldsigs; + long long int now; + long long int msecs; + assert_single_threaded(); time_init(); - block_sigalrm(&oldsigs); - deadline = secs ? time_add(time_now(), secs) : TIME_MIN; - unblock_sigalrm(&oldsigs); + time_refresh(); + + now = time_msec(); + msecs = secs * 1000LL; + deadline = now < LLONG_MAX - msecs ? now + msecs : LLONG_MAX; } /* Like poll(), except: + * + * - The timeout is specified as an absolute time, as defined by + * time_msec(), instead of a duration. * * - On error, returns a negative error code (instead of setting errno). * * - If interrupted by a signal, retries automatically until the original - * 'timeout' expires. (Because of this property, this function will + * timeout is reached. (Because of this property, this function will * never return -EINTR.) * * - As a side effect, refreshes the current time (like time_refresh()). - */ + * + * Stores the number of milliseconds elapsed during poll in '*elapsed'. */ int -time_poll(struct pollfd *pollfds, int n_pollfds, int timeout) +time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, + int *elapsed) { - static long long int last_wakeup; - static struct rusage last_rusage; + 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, &last_rusage); + if (*last_wakeup) { + log_poll_interval(*last_wakeup); + } coverage_clear(); start = time_msec(); blocked = false; + + timeout_when = MIN(timeout_when, deadline); + for (;;) { + long long int now = time_msec(); int time_left; - if (timeout > 0) { - long long int elapsed = time_msec() - start; - time_left = timeout >= elapsed ? timeout - elapsed : 0; + + if (now >= timeout_when) { + time_left = 0; + } else if ((unsigned long long int) timeout_when - now > INT_MAX) { + time_left = INT_MAX; } else { - time_left = timeout; + time_left = timeout_when - now; } retval = poll(pollfds, n_pollfds, time_left); if (retval < 0) { retval = -errno; } + time_refresh(); + if (deadline <= time_msec()) { + fatal_signal_handler(SIGALRM); + if (retval < 0) { + retval = 0; + } + break; + } + if (retval != -EINTR) { break; } - if (!blocked && deadline == TIME_MIN) { + if (!blocked && CACHE_TIME) { block_sigalrm(&oldsigs); blocked = true; } @@ -313,46 +348,16 @@ time_poll(struct pollfd *pollfds, int n_pollfds, int timeout) if (blocked) { unblock_sigalrm(&oldsigs); } - last_wakeup = time_msec(); - getrusage(RUSAGE_SELF, &last_rusage); + *last_wakeup = time_msec(); + refresh_rusage(); + *elapsed = *last_wakeup - start; return retval; } -/* Returns the sum of 'a' and 'b', with saturation on overflow or underflow. */ -static time_t -time_add(time_t a, time_t b) -{ - return (a >= 0 - ? (b > TIME_MAX - a ? TIME_MAX : a + b) - : (b < TIME_MIN - a ? TIME_MIN : a + b)); -} - static void -sigalrm_handler(int sig_nr) +sigalrm_handler(int sig_nr OVS_UNUSED) { - wall_tick = true; - monotonic_tick = true; - if (deadline != TIME_MIN && time_now_sig() > deadline) { - fatal_signal_handler(sig_nr); - } -} - -static void -refresh_wall_if_ticked(void) -{ - assert(inited); - if (wall_tick) { - refresh_wall(); - } -} - -static void -refresh_monotonic_if_ticked(void) -{ - assert(inited); - if (monotonic_tick) { - refresh_monotonic(); - } + monotonic_clock.tick = wall_clock.tick = true; } static void @@ -361,17 +366,13 @@ block_sigalrm(sigset_t *oldsigs) sigset_t sigalrm; sigemptyset(&sigalrm); sigaddset(&sigalrm, SIGALRM); - if (sigprocmask(SIG_BLOCK, &sigalrm, oldsigs)) { - ovs_fatal(errno, "sigprocmask"); - } + xpthread_sigmask(SIG_BLOCK, &sigalrm, oldsigs); } static void unblock_sigalrm(const sigset_t *oldsigs) { - if (sigprocmask(SIG_SETMASK, oldsigs, NULL)) { - ovs_fatal(errno, "sigprocmask"); - } + xpthread_sigmask(SIG_SETMASK, oldsigs, NULL); } long long int @@ -386,6 +387,33 @@ timeval_to_msec(const struct timeval *tv) return (long long int) tv->tv_sec * 1000 + tv->tv_usec / 1000; } +/* Returns the monotonic time at which the "time" module was initialized, in + * milliseconds. */ +long long int +time_boot_msec(void) +{ + time_init(); + return boot_time; +} + +void +xgettimeofday(struct timeval *tv) +{ + if (gettimeofday(tv, NULL) == -1) { + 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"); + } +} + static long long int timeval_diff_msec(const struct timeval *a, const struct timeval *b) { @@ -393,32 +421,41 @@ timeval_diff_msec(const struct timeval *a, const struct timeval *b) } static void -log_poll_interval(long long int last_wakeup, const struct rusage *last_rusage) +timespec_add(struct timespec *sum, + const struct timespec *a, + const struct timespec *b) { - static unsigned int mean_interval; /* In 16ths of a millisecond. */ - static unsigned int n_samples; + struct timespec tmp; - long long int now; - unsigned int interval; /* In 16ths of a millisecond. */ + tmp.tv_sec = a->tv_sec + b->tv_sec; + tmp.tv_nsec = a->tv_nsec + b->tv_nsec; + if (tmp.tv_nsec >= 1000 * 1000 * 1000) { + tmp.tv_nsec -= 1000 * 1000 * 1000; + tmp.tv_sec++; + } - /* 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; + *sum = tmp; +} + +static void +log_poll_interval(long long int last_wakeup) +{ + long long int interval = time_msec() - last_wakeup; - /* Warn if we took too much time between polls. */ - if (n_samples > 10 && interval > mean_interval * 8) { + 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("%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); + 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", @@ -437,19 +474,139 @@ log_poll_interval(long long int last_wakeup, const struct rusage *last_rusage) rusage.ru_nvcsw - last_rusage->ru_nvcsw, rusage.ru_nivcsw - last_rusage->ru_nivcsw); } + coverage_log(); + } +} + +/* CPU usage tracking. */ + +struct cpu_usage { + long long int when; /* Time that this sample was taken. */ + unsigned long long int cpu; /* Total user+system CPU usage when sampled. */ +}; + +struct cpu_tracker { + struct cpu_usage older; + struct cpu_usage newer; + int cpu_usage; - /* Care should be taken in the value chosen for logging. Depending - * on the configuration, syslog can write changes synchronously, - * which can cause the coverage messages to take longer to log - * than the processing delay that triggered it. */ - coverage_log(VLL_INFO, true); + 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; +} - /* 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; +static struct rusage * +get_recent_rusage(void) +{ + 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) +{ + struct cpu_tracker *t = get_cpu_tracker(); + struct rusage *recent_rusage = &t->recent_rusage; + + 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; + } + } } } + +/* Returns an estimate of this process's CPU usage, as a percentage, over the + * past few seconds of wall-clock time. Returns -1 if no estimate is available + * (which will happen if the process has not been running long enough to have + * an estimate, and can happen for other reasons as well). */ +int +get_cpu_usage(void) +{ + return get_cpu_tracker()->cpu_usage; +} + +/* Unixctl interface. */ + +/* "time/stop" stops the monotonic time returned by e.g. time_msec() from + * advancing, except due to later calls to "time/warp". */ +static void +timeval_stop_cb(struct unixctl_conn *conn, + int argc OVS_UNUSED, const char *argv[] OVS_UNUSED, + void *aux OVS_UNUSED) +{ + ovs_rwlock_wrlock(&monotonic_clock.rwlock); + monotonic_clock.stopped = true; + ovs_rwlock_unlock(&monotonic_clock.rwlock); + + unixctl_command_reply(conn, NULL); +} + +/* "time/warp MSECS" advances the current monotonic time by the specified + * number of milliseconds. Unless "time/stop" has also been executed, the + * monotonic clock continues to tick forward at the normal rate afterward. + * + * Does not affect wall clock readings. */ +static void +timeval_warp_cb(struct unixctl_conn *conn, + int argc OVS_UNUSED, const char *argv[], void *aux OVS_UNUSED) +{ + struct timespec ts; + int msecs; + + msecs = atoi(argv[1]); + if (msecs <= 0) { + unixctl_command_reply_error(conn, "invalid MSECS"); + return; + } + + ts.tv_sec = msecs / 1000; + ts.tv_nsec = (msecs % 1000) * 1000 * 1000; + + 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"); +} + +void +timeval_dummy_register(void) +{ + unixctl_command_register("time/stop", "", 0, 0, timeval_stop_cb, NULL); + unixctl_command_register("time/warp", "MSECS", 1, 1, + timeval_warp_cb, NULL); +}