/*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* to CLOCK_REALTIME. */
static clockid_t monotonic_clock;
-/* Has a timer tick occurred?
+/* Has a timer tick occurred? Only relevant if CACHE_TIME is 1.
*
* 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. */
/* 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;
+/* 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 at which to die with SIGALRM (if not TIME_MIN). */
static time_t deadline = TIME_MIN;
VLOG_DBG("monotonic timer not available");
}
- set_up_signal(SA_RESTART);
- set_up_timer();
+ if (CACHE_TIME) {
+ set_up_signal(SA_RESTART);
+ set_up_timer();
+ }
+
boot_time = time_msec();
}
time_postfork(void)
{
time_init();
- set_up_timer();
+
+ 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();
+ }
+ }
}
static void
{
time_init();
- if (monotonic_clock == CLOCK_MONOTONIC) {
- clock_gettime(monotonic_clock, &monotonic_time);
- } else {
- refresh_wall_if_ticked();
- monotonic_time = wall_time;
- }
- timespec_add(&monotonic_time, &monotonic_time, &warp_offset);
+ if (!time_stopped) {
+ if (monotonic_clock == CLOCK_MONOTONIC) {
+ clock_gettime(monotonic_clock, &monotonic_time);
+ } else {
+ refresh_wall_if_ticked();
+ monotonic_time = wall_time;
+ }
+ timespec_add(&monotonic_time, &monotonic_time, &warp_offset);
- monotonic_tick = false;
+ 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. */
+ * automatically at least every TIME_UPDATE_INTERVAL milliseconds. If
+ * CACHE_TIME is 0, we will always refresh the current time so this
+ * function has no effect. */
void
time_refresh(void)
{
sigset_t oldsigs;
time_init();
+
block_sigalrm(&oldsigs);
deadline = secs ? time_add(time_now(), secs) : TIME_MIN;
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:
static void
refresh_wall_if_ticked(void)
{
- if (wall_tick) {
+ if (!CACHE_TIME || wall_tick) {
refresh_wall();
}
}
static void
refresh_monotonic_if_ticked(void)
{
- if (monotonic_tick) {
+ if (!CACHE_TIME || monotonic_tick) {
refresh_monotonic();
}
}
/* 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("%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);
+ 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);
+ }
}
- 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);
- }
-
- /* 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);
+ coverage_log();
}
/* Update exponentially weighted moving average. With these parameters, a
\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)
+{
+ time_stopped = true;
+ 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);
+ timespec_add(&monotonic_time, &monotonic_time, &ts);
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);
}