X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Ftimeval.c;h=88a6679eab039f97676bb44710dc211cb0e51f75;hb=b3e0370a37daeecc44ddaf03bbd98c2e8ff4513d;hp=5e423875852c450dbe212fee47b885b1593ff702;hpb=c69ee87c10818267f991236201150b1fa51ae519;p=sliver-openvswitch.git diff --git a/lib/timeval.c b/lib/timeval.c index 5e4238758..88a6679ea 100644 --- a/lib/timeval.c +++ b/lib/timeval.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -26,19 +26,27 @@ #include #include "coverage.h" #include "fatal-signal.h" +#include "signals.h" #include "util.h" - #include "vlog.h" -#define THIS_MODULE VLM_timeval -/* Initialized? */ -static bool inited; +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; -/* Has a timer tick occurred? */ -static volatile sig_atomic_t tick; +/* Has a timer tick occurred? + * + * 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; /* The current time, as of the last refresh. */ -static struct timeval now; +static struct timespec wall_time; +static struct timespec monotonic_time; /* Time at which to die with SIGALRM (if not TIME_MIN). */ static time_t deadline = TIME_MIN; @@ -46,26 +54,36 @@ static time_t deadline = TIME_MIN; static void set_up_timer(void); static void set_up_signal(int flags); static void sigalrm_handler(int); -static void refresh_if_ticked(void); +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); -/* Initializes the timetracking module. */ -void +/* Initializes the timetracking module. + * + * It is not necessary to call this function directly, because other time + * functions will call it automatically, but it doesn't hurt. */ +static void time_init(void) { + static bool inited; if (inited) { return; } + inited = true; coverage_init(); - inited = true; - gettimeofday(&now, NULL); - tick = false; + if (!clock_gettime(CLOCK_MONOTONIC, &monotonic_time)) { + monotonic_clock = CLOCK_MONOTONIC; + } else { + monotonic_clock = CLOCK_REALTIME; + VLOG_DBG("monotonic timer not available"); + } set_up_signal(SA_RESTART); set_up_timer(); @@ -80,9 +98,7 @@ 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"); - } + xsigaction(SIGALRM, &sa, NULL); } /* Remove SA_RESTART from the flags for SIGALRM, so that any system call that @@ -100,6 +116,7 @@ set_up_signal(int flags) void time_disable_restart(void) { + time_init(); set_up_signal(0); } @@ -109,19 +126,26 @@ time_disable_restart(void) void time_enable_restart(void) { + time_init(); set_up_signal(SA_RESTART); } static void set_up_timer(void) { - struct itimerval itimer; + static timer_t timer_id; /* "static" to avoid apparent memory leak. */ + struct itimerspec itimer; + + if (timer_create(monotonic_clock, NULL, &timer_id)) { + VLOG_FATAL("timer_create failed (%s)", strerror(errno)); + } itimer.it_interval.tv_sec = 0; - itimer.it_interval.tv_usec = TIME_UPDATE_INTERVAL * 1000; + itimer.it_interval.tv_nsec = TIME_UPDATE_INTERVAL * 1000 * 1000; itimer.it_value = itimer.it_interval; - if (setitimer(ITIMER_REAL, &itimer, NULL)) { - ovs_fatal(errno, "setitimer failed"); + + if (timer_settime(timer_id, 0, &itimer, NULL)) { + VLOG_FATAL("timer_settime failed (%s)", strerror(errno)); } } @@ -133,42 +157,101 @@ set_up_timer(void) void time_postfork(void) { + time_init(); set_up_timer(); } +static void +refresh_wall(void) +{ + time_init(); + clock_gettime(CLOCK_REALTIME, &wall_time); + wall_tick = false; +} + +static void +refresh_monotonic(void) +{ + time_init(); + + if (monotonic_clock == CLOCK_MONOTONIC) { + clock_gettime(monotonic_clock, &monotonic_time); + } else { + refresh_wall_if_ticked(); + monotonic_time = wall_time; + } + + 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. */ void time_refresh(void) { - gettimeofday(&now, NULL); - tick = false; + wall_tick = monotonic_tick = true; } -/* Returns the current time, in seconds. */ +/* Returns a monotonic timer, in seconds. */ time_t time_now(void) { - refresh_if_ticked(); - return now.tv_sec; + refresh_monotonic_if_ticked(); + return monotonic_time.tv_sec; } -/* Returns the current time, in ms (within TIME_UPDATE_INTERVAL ms). */ +/* 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) +{ + refresh_wall_if_ticked(); + return wall_time.tv_sec; +} + +/* Returns a monotonic timer, in ms (within TIME_UPDATE_INTERVAL ms). */ long long int time_msec(void) { - refresh_if_ticked(); - return timeval_to_msec(&now); + refresh_monotonic_if_ticked(); + return timespec_to_msec(&monotonic_time); +} + +/* 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 - * '*tv'. */ + * '*ts'. */ void -time_timeval(struct timeval *tv) +time_wall_timespec(struct timespec *ts) { - refresh_if_ticked(); - *tv = now; + refresh_wall_if_ticked(); + *ts = wall_time; } /* Configures the program to die with SIGALRM 'secs' seconds from now, if @@ -198,14 +281,13 @@ int time_poll(struct pollfd *pollfds, int n_pollfds, int timeout) { static long long int last_wakeup; - static struct rusage last_rusage; long long int start; sigset_t oldsigs; bool blocked; int retval; time_refresh(); - log_poll_interval(last_wakeup, &last_rusage); + log_poll_interval(last_wakeup); coverage_clear(); start = time_msec(); blocked = false; @@ -236,7 +318,7 @@ time_poll(struct pollfd *pollfds, int n_pollfds, int timeout) unblock_sigalrm(&oldsigs); } last_wakeup = time_msec(); - getrusage(RUSAGE_SELF, &last_rusage); + refresh_rusage(); return retval; } @@ -252,18 +334,26 @@ time_add(time_t a, time_t b) static void sigalrm_handler(int sig_nr) { - tick = true; - if (deadline != TIME_MIN && time(0) > deadline) { + wall_tick = true; + monotonic_tick = true; + if (deadline != TIME_MIN && time_now_sig() > deadline) { fatal_signal_handler(sig_nr); } } static void -refresh_if_ticked(void) +refresh_wall_if_ticked(void) { - assert(inited); - if (tick) { - time_refresh(); + if (wall_tick) { + refresh_wall(); + } +} + +static void +refresh_monotonic_if_ticked(void) +{ + if (monotonic_tick) { + refresh_monotonic(); } } @@ -273,17 +363,19 @@ block_sigalrm(sigset_t *oldsigs) sigset_t sigalrm; sigemptyset(&sigalrm); sigaddset(&sigalrm, SIGALRM); - if (sigprocmask(SIG_BLOCK, &sigalrm, oldsigs)) { - ovs_fatal(errno, "sigprocmask"); - } + xsigprocmask(SIG_BLOCK, &sigalrm, oldsigs); } static void unblock_sigalrm(const sigset_t *oldsigs) { - if (sigprocmask(SIG_SETMASK, oldsigs, NULL)) { - ovs_fatal(errno, "sigprocmask"); - } + xsigprocmask(SIG_SETMASK, oldsigs, NULL); +} + +long long int +timespec_to_msec(const struct timespec *ts) +{ + return (long long int) ts->tv_sec * 1000 + ts->tv_nsec / (1000 * 1000); } long long int @@ -292,6 +384,14 @@ timeval_to_msec(const struct timeval *tv) return (long long int) tv->tv_sec * 1000 + tv->tv_usec / 1000; } +void +xgettimeofday(struct timeval *tv) +{ + if (gettimeofday(tv, NULL) == -1) { + VLOG_FATAL("gettimeofday failed (%s)", strerror(errno)); + } +} + static long long int timeval_diff_msec(const struct timeval *a, const struct timeval *b) { @@ -299,7 +399,7 @@ 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) +log_poll_interval(long long int last_wakeup) { static unsigned int mean_interval; /* In 16ths of a millisecond. */ static unsigned int n_samples; @@ -312,15 +412,17 @@ log_poll_interval(long long int last_wakeup, const struct rusage *last_rusage) now = time_msec(); interval = MIN(10000, now - last_wakeup) << 4; - /* Warn if we took too much time between polls. */ - if (n_samples > 10 && interval > mean_interval * 8) { + /* 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) { + const struct rusage *last_rusage = get_recent_rusage(); struct rusage rusage; getrusage(RUSAGE_SELF, &rusage); - VLOG_WARN("%u ms poll interval (%lld ms user, %lld ms system) " + VLOG_WARN("%lld ms poll interval (%lld ms user, %lld ms system) " "is over %u times the weighted mean interval %u ms " "(%u samples)", - (interval + 8) / 16, + 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, @@ -344,9 +446,9 @@ log_poll_interval(long long int last_wakeup, const struct rusage *last_rusage) rusage.ru_nivcsw - last_rusage->ru_nivcsw); } - /* 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 + /* 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); } @@ -359,3 +461,55 @@ log_poll_interval(long long int last_wakeup, const struct rusage *last_rusage) mean_interval = interval; } } + +/* 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. */ +}; + +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; + +static struct rusage * +get_recent_rusage(void) +{ + return &recent_rusage; +} + +static void +refresh_rusage(void) +{ + long long int now; + + 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; + } + } +} + +/* 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 cpu_usage; +}