/* * builtin-stat.c * * Builtin stat command: Give a precise performance counters summary * overview about any workload, CPU or specific PID. * * Sample output: $ perf stat ~/hackbench 10 Time: 0.104 Performance counter stats for '/home/mingo/hackbench': 1255.538611 task clock ticks # 10.143 CPU utilization factor 54011 context switches # 0.043 M/sec 385 CPU migrations # 0.000 M/sec 17755 pagefaults # 0.014 M/sec 3808323185 CPU cycles # 3033.219 M/sec 1575111190 instructions # 1254.530 M/sec 17367895 cache references # 13.833 M/sec 7674421 cache misses # 6.112 M/sec Wall-clock time elapsed: 123.786620 msecs * * Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com> * * Improvements and fixes by: * * Arjan van de Ven <arjan@linux.intel.com> * Yanmin Zhang <yanmin.zhang@intel.com> * Wu Fengguang <fengguang.wu@intel.com> * Mike Galbraith <efault@gmx.de> * Paul Mackerras <paulus@samba.org> * Jaswinder Singh Rajput <jaswinder@kernel.org> * * Released under the GPL v2. (and only v2, not any later version) */ #include "perf.h" #include "builtin.h" #include "util/util.h" #include "util/parse-options.h" #include "util/parse-events.h" #include "util/event.h" #include "util/debug.h" #include <sys/prctl.h> #include <math.h> static struct perf_event_attr default_attrs[] = { { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK }, { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES}, { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_MIGRATIONS }, { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS }, { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES }, { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS }, { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_REFERENCES}, { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_MISSES }, }; static int system_wide = 0; static unsigned int nr_cpus = 0; static int run_idx = 0; static int run_count = 1; static int inherit = 1; static int scale = 1; static int target_pid = -1; static int null_run = 0; static int fd[MAX_NR_CPUS][MAX_COUNTERS]; static int event_scaled[MAX_COUNTERS]; struct stats { double n, mean, M2; }; static void update_stats(struct stats *stats, u64 val) { double delta; stats->n++; delta = val - stats->mean; stats->mean += delta / stats->n; stats->M2 += delta*(val - stats->mean); } static double avg_stats(struct stats *stats) { return stats->mean; } /* * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance * * (\Sum n_i^2) - ((\Sum n_i)^2)/n * s^2 = ------------------------------- * n - 1 * * http://en.wikipedia.org/wiki/Stddev * * The std dev of the mean is related to the std dev by: * * s * s_mean = ------- * sqrt(n) * */ static double stddev_stats(struct stats *stats) { double variance = stats->M2 / (stats->n - 1); double variance_mean = variance / stats->n; return sqrt(variance_mean); } struct stats event_res_stats[MAX_COUNTERS][3]; struct stats runtime_nsecs_stats; struct stats walltime_nsecs_stats; struct stats runtime_cycles_stats; #define MATCH_EVENT(t, c, counter) \ (attrs[counter].type == PERF_TYPE_##t && \ attrs[counter].config == PERF_COUNT_##c) #define ERR_PERF_OPEN \ "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n" static void create_perf_stat_counter(int counter, int pid) { struct perf_event_attr *attr = attrs + counter; if (scale) attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED | PERF_FORMAT_TOTAL_TIME_RUNNING; if (system_wide) { unsigned int cpu; for (cpu = 0; cpu < nr_cpus; cpu++) { fd[cpu][counter] = sys_perf_event_open(attr, -1, cpu, -1, 0); if (fd[cpu][counter] < 0 && verbose) fprintf(stderr, ERR_PERF_OPEN, counter, fd[cpu][counter], strerror(errno)); } } else { attr->inherit = inherit; attr->disabled = 1; attr->enable_on_exec = 1; fd[0][counter] = sys_perf_event_open(attr, pid, -1, -1, 0); if (fd[0][counter] < 0 && verbose) fprintf(stderr, ERR_PERF_OPEN, counter, fd[0][counter], strerror(errno)); } } /* * Does the counter have nsecs as a unit? */ static inline int nsec_counter(int counter) { if (MATCH_EVENT(SOFTWARE, SW_CPU_CLOCK, counter) || MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) return 1; return 0; } /* * Read out the results of a single counter: */ static void read_counter(int counter) { u64 count[3], single_count[3]; unsigned int cpu; size_t res, nv; int scaled; int i; count[0] = count[1] = count[2] = 0; nv = scale ? 3 : 1; for (cpu = 0; cpu < nr_cpus; cpu++) { if (fd[cpu][counter] < 0) continue; res = read(fd[cpu][counter], single_count, nv * sizeof(u64)); assert(res == nv * sizeof(u64)); close(fd[cpu][counter]); fd[cpu][counter] = -1; count[0] += single_count[0]; if (scale) { count[1] += single_count[1]; count[2] += single_count[2]; } } scaled = 0; if (scale) { if (count[2] == 0) { event_scaled[counter] = -1; count[0] = 0; return; } if (count[2] < count[1]) { event_scaled[counter] = 1; count[0] = (unsigned long long) ((double)count[0] * count[1] / count[2] + 0.5); } } for (i = 0; i < 3; i++) update_stats(&event_res_stats[counter][i], count[i]); if (verbose) { fprintf(stderr, "%s: %Ld %Ld %Ld\n", event_name(counter), count[0], count[1], count[2]); } /* * Save the full runtime - to allow normalization during printout: */ if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) update_stats(&runtime_nsecs_stats, count[0]); if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter)) update_stats(&runtime_cycles_stats, count[0]); } static int run_perf_stat(int argc __used, const char **argv) { unsigned long long t0, t1; int status = 0; int counter; int pid; int child_ready_pipe[2], go_pipe[2]; char buf; if (!system_wide) nr_cpus = 1; if (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0) { perror("failed to create pipes"); exit(1); } if ((pid = fork()) < 0) perror("failed to fork"); if (!pid) { close(child_ready_pipe[0]); close(go_pipe[1]); fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC); /* * Do a dummy execvp to get the PLT entry resolved, * so we avoid the resolver overhead on the real * execvp call. */ execvp("", (char **)argv); /* * Tell the parent we're ready to go */ close(child_ready_pipe[1]); /* * Wait until the parent tells us to go. */ if (read(go_pipe[0], &buf, 1) == -1) perror("unable to read pipe"); execvp(argv[0], (char **)argv); perror(argv[0]); exit(-1); } /* * Wait for the child to be ready to exec. */ close(child_ready_pipe[1]); close(go_pipe[0]); if (read(child_ready_pipe[0], &buf, 1) == -1) perror("unable to read pipe"); close(child_ready_pipe[0]); for (counter = 0; counter < nr_counters; counter++) create_perf_stat_counter(counter, pid); /* * Enable counters and exec the command: */ t0 = rdclock(); close(go_pipe[1]); wait(&status); t1 = rdclock(); update_stats(&walltime_nsecs_stats, t1 - t0); for (counter = 0; counter < nr_counters; counter++) read_counter(counter); return WEXITSTATUS(status); } static void print_noise(int counter, double avg) { if (run_count == 1) return; fprintf(stderr, " ( +- %7.3f%% )", 100 * stddev_stats(&event_res_stats[counter][0]) / avg); } static void nsec_printout(int counter, double avg) { double msecs = avg / 1e6; fprintf(stderr, " %14.6f %-24s", msecs, event_name(counter)); if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) { fprintf(stderr, " # %10.3f CPUs ", avg / avg_stats(&walltime_nsecs_stats)); } } static void abs_printout(int counter, double avg) { double total, ratio = 0.0; fprintf(stderr, " %14.0f %-24s", avg, event_name(counter)); if (MATCH_EVENT(HARDWARE, HW_INSTRUCTIONS, counter)) { total = avg_stats(&runtime_cycles_stats); if (total) ratio = avg / total; fprintf(stderr, " # %10.3f IPC ", ratio); } else { total = avg_stats(&runtime_nsecs_stats); if (total) ratio = 1000.0 * avg / total; fprintf(stderr, " # %10.3f M/sec", ratio); } } /* * Print out the results of a single counter: */ static void print_counter(int counter) { double avg = avg_stats(&event_res_stats[counter][0]); int scaled = event_scaled[counter]; if (scaled == -1) { fprintf(stderr, " %14s %-24s\n", "<not counted>", event_name(counter)); return; } if (nsec_counter(counter)) nsec_printout(counter, avg); else abs_printout(counter, avg); print_noise(counter, avg); if (scaled) { double avg_enabled, avg_running; avg_enabled = avg_stats(&event_res_stats[counter][1]); avg_running = avg_stats(&event_res_stats[counter][2]); fprintf(stderr, " (scaled from %.2f%%)", 100 * avg_running / avg_enabled); } fprintf(stderr, "\n"); } static void print_stat(int argc, const char **argv) { int i, counter; fflush(stdout); fprintf(stderr, "\n"); fprintf(stderr, " Performance counter stats for \'%s", argv[0]); for (i = 1; i < argc; i++) fprintf(stderr, " %s", argv[i]); fprintf(stderr, "\'"); if (run_count > 1) fprintf(stderr, " (%d runs)", run_count); fprintf(stderr, ":\n\n"); for (counter = 0; counter < nr_counters; counter++) print_counter(counter); fprintf(stderr, "\n"); fprintf(stderr, " %14.9f seconds time elapsed", avg_stats(&walltime_nsecs_stats)/1e9); if (run_count > 1) { fprintf(stderr, " ( +- %7.3f%% )", 100*stddev_stats(&walltime_nsecs_stats) / avg_stats(&walltime_nsecs_stats)); } fprintf(stderr, "\n\n"); } static volatile int signr = -1; static void skip_signal(int signo) { signr = signo; } static void sig_atexit(void) { if (signr == -1) return; signal(signr, SIG_DFL); kill(getpid(), signr); } static const char * const stat_usage[] = { "perf stat [<options>] <command>", NULL }; static const struct option options[] = { OPT_CALLBACK('e', "event", NULL, "event", "event selector. use 'perf list' to list available events", parse_events), OPT_BOOLEAN('i', "inherit", &inherit, "child tasks inherit counters"), OPT_INTEGER('p', "pid", &target_pid, "stat events on existing pid"), OPT_BOOLEAN('a', "all-cpus", &system_wide, "system-wide collection from all CPUs"), OPT_BOOLEAN('c', "scale", &scale, "scale/normalize counters"), OPT_BOOLEAN('v', "verbose", &verbose, "be more verbose (show counter open errors, etc)"), OPT_INTEGER('r', "repeat", &run_count, "repeat command and print average + stddev (max: 100)"), OPT_BOOLEAN('n', "null", &null_run, "null run - dont start any counters"), OPT_END() }; int cmd_stat(int argc, const char **argv, const char *prefix __used) { int status; argc = parse_options(argc, argv, options, stat_usage, PARSE_OPT_STOP_AT_NON_OPTION); if (!argc) usage_with_options(stat_usage, options); if (run_count <= 0) usage_with_options(stat_usage, options); /* Set attrs and nr_counters if no event is selected and !null_run */ if (!null_run && !nr_counters) { memcpy(attrs, default_attrs, sizeof(default_attrs)); nr_counters = ARRAY_SIZE(default_attrs); } nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); assert(nr_cpus <= MAX_NR_CPUS); assert((int)nr_cpus >= 0); /* * We dont want to block the signals - that would cause * child tasks to inherit that and Ctrl-C would not work. * What we want is for Ctrl-C to work in the exec()-ed * task, but being ignored by perf stat itself: */ atexit(sig_atexit); signal(SIGINT, skip_signal); signal(SIGALRM, skip_signal); signal(SIGABRT, skip_signal); status = 0; for (run_idx = 0; run_idx < run_count; run_idx++) { if (run_count != 1 && verbose) fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1); status = run_perf_stat(argc, argv); } print_stat(argc, argv); return status; }