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