X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Ftimeval.c;h=9029faa8e8ea8f8c8b4cab04826e3cc1a80c0c1a;hb=aa6c9932f2937fa9a2140ec1737668eb9105b0b5;hp=3d339e4ecdb988b4f02bbdc717e72038f1d692af;hpb=49635519bae2c14e44744825c907ccee9216bf90;p=sliver-openvswitch.git diff --git a/lib/timeval.c b/lib/timeval.c index 3d339e4ec..9029faa8e 100644 --- a/lib/timeval.c +++ b/lib/timeval.c @@ -18,6 +18,9 @@ #include "timeval.h" #include #include +#if HAVE_EXECINFO_H +#include +#endif #include #include #include @@ -27,12 +30,17 @@ #include #include "coverage.h" #include "dummy.h" +#include "dynamic-string.h" #include "fatal-signal.h" #include "signals.h" #include "unixctl.h" #include "util.h" #include "vlog.h" +#ifndef HAVE_EXECINFO_H +#define HAVE_EXECINFO_H 0 +#endif + VLOG_DEFINE_THIS_MODULE(timeval); /* The clock to use for measuring time intervals. This is CLOCK_MONOTONIC by @@ -40,7 +48,7 @@ VLOG_DEFINE_THIS_MODULE(timeval); * to CLOCK_REALTIME. */ static clockid_t monotonic_clock; -/* Has a timer tick occurred? Only relevant if CACHE_TIME is 1. +/* 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. */ @@ -58,15 +66,24 @@ static long long int boot_time; static struct timespec warp_offset; /* Offset added to monotonic_time. */ static bool time_stopped; /* Disables real-time updates, if true. */ -/* Time at which to die with SIGALRM (if not TIME_MIN). */ -static time_t deadline = TIME_MIN; +/* Time in milliseconds at which to die with SIGALRM (if not LLONG_MAX). */ +static long long int deadline = LLONG_MAX; + +struct trace { + void *backtrace[32]; /* Populated by backtrace(). */ + size_t n_frames; /* Number of frames in 'backtrace'. */ +}; + +#define MAX_TRACES 50 +static struct unixctl_conn *backtrace_conn = NULL; +static struct trace *traces = NULL; +static size_t n_traces = 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); @@ -74,17 +91,29 @@ 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); +static void trace_run(void); +static unixctl_cb_func backtrace_cb; /* Initializes the timetracking module, if not already initialized. */ static void time_init(void) { static bool inited; + + /* The best place to do this is probably a timeval_run() function. + * However, none exists and this function is usually so fast that doing it + * here seems fine for now. */ + trace_run(); + if (inited) { return; } inited = true; + if (HAVE_EXECINFO_H && CACHE_TIME) { + unixctl_command_register("backtrace", "", 0, 0, backtrace_cb, NULL); + } + coverage_init(); if (!clock_gettime(CLOCK_MONOTONIC, &monotonic_time)) { @@ -94,10 +123,8 @@ time_init(void) VLOG_DBG("monotonic timer not available"); } - if (CACHE_TIME) { - set_up_signal(SA_RESTART); - set_up_timer(); - } + set_up_signal(SA_RESTART); + set_up_timer(); boot_time = time_msec(); } @@ -149,6 +176,10 @@ set_up_timer(void) static timer_t timer_id; /* "static" to avoid apparent memory leak. */ struct itimerspec itimer; + if (!CACHE_TIME) { + return; + } + if (timer_create(monotonic_clock, NULL, &timer_id)) { VLOG_FATAL("timer_create failed (%s)", strerror(errno)); } @@ -171,16 +202,7 @@ void time_postfork(void) { time_init(); - - if (CACHE_TIME) { - set_up_timer(); - } else { - /* If we are not caching kernel time, the only reason the timer should - * exist is if time_alarm() was called and deadline is set */ - if (deadline != TIME_MIN) { - set_up_timer(); - } - } + set_up_timer(); } static void @@ -212,7 +234,7 @@ refresh_monotonic(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 0, we will always refresh the current time so this + * CACHE_TIME is false, we will always refresh the current time so this * function has no effect. */ void time_refresh(void) @@ -228,17 +250,6 @@ time_now(void) return monotonic_time.tv_sec; } -/* Same as time_now() except does not write to static variables, for use in - * signal handlers. */ -static time_t -time_now_sig(void) -{ - struct timespec cur_time; - - clock_gettime(monotonic_clock, &cur_time); - return cur_time.tv_sec; -} - /* Returns the current time, in seconds. */ time_t time_wall(void) @@ -286,20 +297,20 @@ time_wall_timespec(struct timespec *ts) void time_alarm(unsigned int secs) { + long long int now; + long long int msecs; + sigset_t oldsigs; time_init(); + time_refresh(); + + now = time_msec(); + msecs = secs * 1000; block_sigalrm(&oldsigs); - deadline = secs ? time_add(time_now(), secs) : TIME_MIN; + deadline = now < LLONG_MAX - msecs ? now + msecs : LLONG_MAX; unblock_sigalrm(&oldsigs); - - if (!CACHE_TIME) { - /* If we aren't timing the gaps between kernel time refreshes we need to - * to start the timer up now */ - set_up_signal(SA_RESTART); - set_up_timer(); - } } /* Like poll(), except: @@ -320,17 +331,22 @@ int time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, int *elapsed) { - static long long int last_wakeup; + static long long int last_wakeup = 0; long long int start; sigset_t oldsigs; bool blocked; int retval; time_refresh(); - log_poll_interval(last_wakeup); + 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; @@ -347,12 +363,21 @@ time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, 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 && !backtrace_conn) { block_sigalrm(&oldsigs); blocked = true; } @@ -366,23 +391,19 @@ time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, 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); + +#if HAVE_EXECINFO_H + if (backtrace_conn && n_traces < MAX_TRACES) { + struct trace *trace = &traces[n_traces++]; + trace->n_frames = backtrace(trace->backtrace, + ARRAY_SIZE(trace->backtrace)); } +#endif } static void @@ -471,66 +492,40 @@ 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) { + 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. */ @@ -584,6 +579,47 @@ get_cpu_usage(void) { return cpu_usage; } + +static void +trace_run(void) +{ +#if HAVE_EXECINFO_H + if (backtrace_conn && n_traces >= MAX_TRACES) { + struct unixctl_conn *reply_conn = backtrace_conn; + struct ds ds = DS_EMPTY_INITIALIZER; + sigset_t oldsigs; + size_t i; + + block_sigalrm(&oldsigs); + + for (i = 0; i < n_traces; i++) { + struct trace *trace = &traces[i]; + char **frame_strs; + size_t j; + + frame_strs = backtrace_symbols(trace->backtrace, trace->n_frames); + + ds_put_format(&ds, "Backtrace %zu\n", i + 1); + for (j = 0; j < trace->n_frames; j++) { + ds_put_format(&ds, "%s\n", frame_strs[j]); + } + ds_put_cstr(&ds, "\n"); + + free(frame_strs); + } + + free(traces); + traces = NULL; + n_traces = 0; + backtrace_conn = NULL; + + unblock_sigalrm(&oldsigs); + + unixctl_command_reply(reply_conn, ds_cstr(&ds)); + ds_destroy(&ds); + } +#endif +} /* Unixctl interface. */ @@ -623,6 +659,28 @@ timeval_warp_cb(struct unixctl_conn *conn, unixctl_command_reply(conn, "warped"); } +static void +backtrace_cb(struct unixctl_conn *conn, + int argc OVS_UNUSED, const char *argv[] OVS_UNUSED, + void *aux OVS_UNUSED) +{ + sigset_t oldsigs; + + assert(HAVE_EXECINFO_H && CACHE_TIME); + + if (backtrace_conn) { + unixctl_command_reply_error(conn, "In Use"); + return; + } + assert(!traces); + + block_sigalrm(&oldsigs); + backtrace_conn = conn; + traces = xmalloc(MAX_TRACES * sizeof *traces); + n_traces = 0; + unblock_sigalrm(&oldsigs); +} + void timeval_dummy_register(void) {