/*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
+ * 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>
-#if HAVE_EXECINFO_H
-#include <execinfo.h>
-#endif
#include <poll.h>
#include <signal.h>
#include <stdlib.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"
-#ifndef HAVE_EXECINFO_H
-#define HAVE_EXECINFO_H 0
+/* backtrace() from <execinfo.h> is really useful, but it is not signal safe
+ * everywhere, such as on x86-64. */
+#if HAVE_BACKTRACE && !defined __x86_64__
+# define USE_BACKTRACE 1
+# include <execinfo.h>
+#else
+# define USE_BACKTRACE 0
#endif
VLOG_DEFINE_THIS_MODULE(timeval);
struct trace {
void *backtrace[32]; /* Populated by backtrace(). */
size_t n_frames; /* Number of frames in 'backtrace'. */
+
+ /* format_backtraces() helper data. */
+ struct hmap_node node;
+ size_t count;
};
#define MAX_TRACES 50
-static struct unixctl_conn *backtrace_conn = NULL;
-static struct trace *traces = NULL;
-static size_t n_traces = 0;
+static struct trace traces[MAX_TRACES];
+static size_t trace_head = 0;
static void set_up_timer(void);
static void set_up_signal(int flags);
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;
+#if !USE_BACKTRACE
+static int
+backtrace(void **buffer OVS_UNUSED, int size OVS_UNUSED)
+{
+ NOT_REACHED();
+}
+
+static char **
+backtrace_symbols(void *const *buffer OVS_UNUSED, int size OVS_UNUSED)
+{
+ NOT_REACHED();
+}
+#endif /* !USE_BACKTRACE */
+
/* 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) {
+ /* The implementation of backtrace() in glibc does some one time
+ * initialization which is not signal safe. This can cause deadlocks if
+ * run from the signal handler. As a workaround, force the initialization
+ * to happen here. */
+ if (USE_BACKTRACE) {
+ void *bt[1];
+
+ backtrace(bt, ARRAY_SIZE(bt));
+ }
+
+ memset(traces, 0, sizeof traces);
+
+ if (USE_BACKTRACE && CACHE_TIME) {
unixctl_command_register("backtrace", "", 0, 0, backtrace_cb, NULL);
}
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)
{
long long int now;
long long int msecs;
- sigset_t oldsigs;
-
+ assert_single_threaded();
time_init();
time_refresh();
now = time_msec();
- msecs = secs * 1000;
-
- block_sigalrm(&oldsigs);
+ msecs = secs * 1000LL;
deadline = now < LLONG_MAX - msecs ? now + msecs : LLONG_MAX;
- unblock_sigalrm(&oldsigs);
}
/* Like poll(), except:
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;
break;
}
- if (!blocked && !CACHE_TIME) {
+ if (!blocked && CACHE_TIME) {
block_sigalrm(&oldsigs);
blocked = true;
}
wall_tick = true;
monotonic_tick = true;
-#if HAVE_EXECINFO_H
- if (backtrace_conn && n_traces < MAX_TRACES) {
- struct trace *trace = &traces[n_traces++];
+ if (USE_BACKTRACE && CACHE_TIME) {
+ struct trace *trace = &traces[trace_head];
+
trace->n_frames = backtrace(trace->backtrace,
ARRAY_SIZE(trace->backtrace));
+ trace_head = (trace_head + 1) % MAX_TRACES;
}
-#endif
}
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
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 && !warp_offset.tv_sec && !warp_offset.tv_nsec) {
+ 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;
- }
}
\f
/* CPU usage tracking. */
return cpu_usage;
}
-static void
-trace_run(void)
+static uint32_t
+hash_trace(struct trace *trace)
{
-#if HAVE_EXECINFO_H
- if (backtrace_conn && n_traces >= MAX_TRACES) {
- struct unixctl_conn *reply_conn = backtrace_conn;
- struct ds ds = DS_EMPTY_INITIALIZER;
+ return hash_bytes(trace->backtrace,
+ trace->n_frames * sizeof *trace->backtrace, 0);
+}
+
+static struct trace *
+trace_map_lookup(struct hmap *trace_map, struct trace *key)
+{
+ struct trace *value;
+
+ HMAP_FOR_EACH_WITH_HASH (value, node, hash_trace(key), trace_map) {
+ if (key->n_frames == value->n_frames
+ && !memcmp(key->backtrace, value->backtrace,
+ key->n_frames * sizeof *key->backtrace)) {
+ return value;
+ }
+ }
+ return NULL;
+}
+
+/* Appends a string to 'ds' representing backtraces recorded at regular
+ * intervals in the recent past. This information can be used to get a sense
+ * of what the process has been spending the majority of time doing. Will
+ * ommit any backtraces which have not occurred at least 'min_count' times. */
+void
+format_backtraces(struct ds *ds, size_t min_count)
+{
+ time_init();
+
+ if (USE_BACKTRACE && CACHE_TIME) {
+ struct hmap trace_map = HMAP_INITIALIZER(&trace_map);
+ struct trace *trace, *next;
sigset_t oldsigs;
size_t i;
block_sigalrm(&oldsigs);
- for (i = 0; i < n_traces; i++) {
+ for (i = 0; i < MAX_TRACES; i++) {
struct trace *trace = &traces[i];
+ struct trace *map_trace;
+
+ if (!trace->n_frames) {
+ continue;
+ }
+
+ map_trace = trace_map_lookup(&trace_map, trace);
+ if (map_trace) {
+ map_trace->count++;
+ } else {
+ hmap_insert(&trace_map, &trace->node, hash_trace(trace));
+ trace->count = 1;
+ }
+ }
+
+ HMAP_FOR_EACH_SAFE (trace, next, node, &trace_map) {
char **frame_strs;
size_t j;
+ hmap_remove(&trace_map, &trace->node);
+
+ if (trace->count < min_count) {
+ continue;
+ }
+
frame_strs = backtrace_symbols(trace->backtrace, trace->n_frames);
- ds_put_format(&ds, "Backtrace %zu\n", i + 1);
+ ds_put_format(ds, "Count %zu\n", trace->count);
for (j = 0; j < trace->n_frames; j++) {
- ds_put_format(&ds, "%s\n", frame_strs[j]);
+ ds_put_format(ds, "%s\n", frame_strs[j]);
}
- ds_put_cstr(&ds, "\n");
+ ds_put_cstr(ds, "\n");
free(frame_strs);
}
+ hmap_destroy(&trace_map);
- free(traces);
- traces = NULL;
- n_traces = 0;
- backtrace_conn = NULL;
-
+ ds_chomp(ds, '\n');
unblock_sigalrm(&oldsigs);
-
- unixctl_command_reply(reply_conn, ds_cstr(&ds));
- ds_destroy(&ds);
}
-#endif
}
\f
/* Unixctl interface. */
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);
+ struct ds ds = DS_EMPTY_INITIALIZER;
- block_sigalrm(&oldsigs);
- backtrace_conn = conn;
- traces = xmalloc(MAX_TRACES * sizeof *traces);
- n_traces = 0;
- unblock_sigalrm(&oldsigs);
+ ovs_assert(USE_BACKTRACE && CACHE_TIME);
+ format_backtraces(&ds, 0);
+ unixctl_command_reply(conn, ds_cstr(&ds));
+ ds_destroy(&ds);
}
void
git://git.onelab.eu / sliver-openvswitch.git / blobdiff