X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Ftimeval.c;h=302224ac10639f265410a4e8f2133ba4718e9b92;hb=4cceacb94cfc1d75a961d3d746d2ae369c397ae5;hp=b60ece9e3b46e5b6efa14bd8b77e8ed6780a8370;hpb=a5f607bc8994e5ed870a62062df54e1b5753c6a2;p=openvswitch diff --git a/lib/timeval.c b/lib/timeval.c index b60ece9e..302224ac 100644 --- a/lib/timeval.c +++ b/lib/timeval.c @@ -1,5 +1,5 @@ /* - * 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. @@ -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? +/* 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)) { @@ -96,6 +125,7 @@ time_init(void) set_up_signal(SA_RESTART); set_up_timer(); + boot_time = time_msec(); } @@ -146,6 +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)); } @@ -199,7 +233,9 @@ 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. */ + * 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) { @@ -214,17 +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) @@ -272,11 +297,19 @@ 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); } @@ -309,6 +342,9 @@ time_poll(struct pollfd *pollfds, int n_pollfds, long long int timeout_when, coverage_clear(); start = time_msec(); blocked = false; + + timeout_when = MIN(timeout_when, deadline); + for (;;) { long long int now = time_msec(); int time_left; @@ -325,12 +361,21 @@ 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; } @@ -344,29 +389,25 @@ 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 refresh_wall_if_ticked(void) { - if (wall_tick) { + if (!CACHE_TIME || wall_tick) { refresh_wall(); } } @@ -374,7 +415,7 @@ refresh_wall_if_ticked(void) static void refresh_monotonic_if_ticked(void) { - if (monotonic_tick) { + if (!CACHE_TIME || monotonic_tick) { refresh_monotonic(); } } @@ -562,6 +603,47 @@ 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. */ @@ -601,6 +683,28 @@ 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) {