/*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 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.
#include <config.h>
#include "timeval.h"
-#include <assert.h>
#include <errno.h>
#include <poll.h>
+#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#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"
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'. */
-/* 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;
+ /* 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. */
+
+ /* 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;
-/* Fixed monotonic time offset, for use by unit tests. */
-static struct timespec warp_offset;
+/* Monotonic time in milliseconds at which to die with SIGALRM (if not
+ * LLONG_MAX). */
+static long long int deadline = LLONG_MAX;
-/* Time at which to die with SIGALRM (if not TIME_MIN). */
-static time_t deadline = TIME_MIN;
+/* 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);
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
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 (timer_create(monotonic_clock, NULL, &timer_id)) {
- VLOG_FATAL("timer_create failed (%s)", strerror(errno));
+ 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;
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));
}
}
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();
+ 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);
}
- timespec_add(&monotonic_time, &monotonic_time, &warp_offset);
-
- 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
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:
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;
+
+ timeout_when = MIN(timeout_when, deadline);
+
for (;;) {
long long int now = time_msec();
int 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;
}
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;
}
-/* 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)
-{
- if (wall_tick) {
- refresh_wall();
- }
-}
-
-static void
-refresh_monotonic_if_ticked(void)
-{
- if (monotonic_tick) {
- refresh_monotonic();
- }
+ monotonic_clock.tick = wall_clock.tick = true;
}
static void
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
}
/* Returns the monotonic time at which the "time" module was initialized, in
- * milliseconds(). */
+ * milliseconds. */
long long int
time_boot_msec(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");
}
}
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;
+ long long int interval = time_msec() - last_wakeup;
- /* 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) {
+ 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",
rusage.ru_nvcsw - last_rusage->ru_nvcsw,
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
- * than the processing delay that triggered it. */
- coverage_log(VLL_INFO, true);
- }
-
- /* 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;
+ coverage_log();
}
}
\f
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;
+ }
}
}
}
int
get_cpu_usage(void)
{
- return cpu_usage;
+ return get_cpu_tracker()->cpu_usage;
}
\f
/* 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)
ts.tv_sec = msecs / 1000;
ts.tv_nsec = (msecs % 1000) * 1000 * 1000;
- timespec_add(&warp_offset, &warp_offset, &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");
}
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);
}
+
+
+
+/* strftime() with an extension for high-resolution timestamps. Any '#'s in
+ * 'format' will be replaced by subseconds, e.g. use "%S.###" to obtain results
+ * like "01.123". */
+size_t
+strftime_msec(char *s, size_t max, const char *format,
+ const struct tm_msec *tm)
+{
+ size_t n;
+
+ n = strftime(s, max, format, &tm->tm);
+ if (n) {
+ char decimals[4];
+ char *p;
+
+ sprintf(decimals, "%03d", tm->msec);
+ for (p = strchr(s, '#'); p; p = strchr(p, '#')) {
+ char *d = decimals;
+ while (*p == '#') {
+ *p++ = *d ? *d++ : '0';
+ }
+ }
+ }
+
+ return n;
+}
+
+struct tm_msec *
+localtime_msec(long long int now, struct tm_msec *result)
+{
+ time_t now_sec = now / 1000;
+ localtime_r(&now_sec, &result->tm);
+ result->msec = now % 1000;
+ return result;
+}
+
+struct tm_msec *
+gmtime_msec(long long int now, struct tm_msec *result)
+{
+ time_t now_sec = now / 1000;
+ gmtime_r(&now_sec, &result->tm);
+ result->msec = now % 1000;
+ return result;
+}
projects / cascardo / ovs.git / blobdiff