4 * Builtin stat command: Give a precise performance counters summary
5 * overview about any workload, CPU or specific PID.
9 $ perf stat ~/hackbench 10
12 Performance counter stats for '/home/mingo/hackbench':
14 1255.538611 task clock ticks # 10.143 CPU utilization factor
15 54011 context switches # 0.043 M/sec
16 385 CPU migrations # 0.000 M/sec
17 17755 pagefaults # 0.014 M/sec
18 3808323185 CPU cycles # 3033.219 M/sec
19 1575111190 instructions # 1254.530 M/sec
20 17367895 cache references # 13.833 M/sec
21 7674421 cache misses # 6.112 M/sec
23 Wall-clock time elapsed: 123.786620 msecs
26 * Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com>
28 * Improvements and fixes by:
30 * Arjan van de Ven <arjan@linux.intel.com>
31 * Yanmin Zhang <yanmin.zhang@intel.com>
32 * Wu Fengguang <fengguang.wu@intel.com>
33 * Mike Galbraith <efault@gmx.de>
34 * Paul Mackerras <paulus@samba.org>
35 * Jaswinder Singh Rajput <jaswinder@kernel.org>
37 * Released under the GPL v2. (and only v2, not any later version)
42 #include "util/util.h"
43 #include "util/parse-options.h"
44 #include "util/parse-events.h"
45 #include "util/event.h"
46 #include "util/debug.h"
47 #include "util/header.h"
49 #include <sys/prctl.h>
52 static struct perf_event_attr default_attrs
[] = {
54 { .type
= PERF_TYPE_SOFTWARE
, .config
= PERF_COUNT_SW_TASK_CLOCK
},
55 { .type
= PERF_TYPE_SOFTWARE
, .config
= PERF_COUNT_SW_CONTEXT_SWITCHES
},
56 { .type
= PERF_TYPE_SOFTWARE
, .config
= PERF_COUNT_SW_CPU_MIGRATIONS
},
57 { .type
= PERF_TYPE_SOFTWARE
, .config
= PERF_COUNT_SW_PAGE_FAULTS
},
59 { .type
= PERF_TYPE_HARDWARE
, .config
= PERF_COUNT_HW_CPU_CYCLES
},
60 { .type
= PERF_TYPE_HARDWARE
, .config
= PERF_COUNT_HW_INSTRUCTIONS
},
61 { .type
= PERF_TYPE_HARDWARE
, .config
= PERF_COUNT_HW_BRANCH_INSTRUCTIONS
},
62 { .type
= PERF_TYPE_HARDWARE
, .config
= PERF_COUNT_HW_BRANCH_MISSES
},
63 { .type
= PERF_TYPE_HARDWARE
, .config
= PERF_COUNT_HW_CACHE_REFERENCES
},
64 { .type
= PERF_TYPE_HARDWARE
, .config
= PERF_COUNT_HW_CACHE_MISSES
},
68 static int system_wide
= 0;
69 static unsigned int nr_cpus
= 0;
70 static int run_idx
= 0;
72 static int run_count
= 1;
73 static int inherit
= 1;
75 static pid_t target_pid
= -1;
76 static pid_t child_pid
= -1;
77 static int null_run
= 0;
79 static int fd
[MAX_NR_CPUS
][MAX_COUNTERS
];
81 static int event_scaled
[MAX_COUNTERS
];
83 static volatile int done
= 0;
90 static void update_stats(struct stats
*stats
, u64 val
)
95 delta
= val
- stats
->mean
;
96 stats
->mean
+= delta
/ stats
->n
;
97 stats
->M2
+= delta
*(val
- stats
->mean
);
100 static double avg_stats(struct stats
*stats
)
106 * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
108 * (\Sum n_i^2) - ((\Sum n_i)^2)/n
109 * s^2 = -------------------------------
112 * http://en.wikipedia.org/wiki/Stddev
114 * The std dev of the mean is related to the std dev by:
121 static double stddev_stats(struct stats
*stats
)
123 double variance
= stats
->M2
/ (stats
->n
- 1);
124 double variance_mean
= variance
/ stats
->n
;
126 return sqrt(variance_mean
);
129 struct stats event_res_stats
[MAX_COUNTERS
][3];
130 struct stats runtime_nsecs_stats
;
131 struct stats walltime_nsecs_stats
;
132 struct stats runtime_cycles_stats
;
133 struct stats runtime_branches_stats
;
135 #define MATCH_EVENT(t, c, counter) \
136 (attrs[counter].type == PERF_TYPE_##t && \
137 attrs[counter].config == PERF_COUNT_##c)
139 #define ERR_PERF_OPEN \
140 "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n"
142 static void create_perf_stat_counter(int counter
, int pid
)
144 struct perf_event_attr
*attr
= attrs
+ counter
;
147 attr
->read_format
= PERF_FORMAT_TOTAL_TIME_ENABLED
|
148 PERF_FORMAT_TOTAL_TIME_RUNNING
;
153 for (cpu
= 0; cpu
< nr_cpus
; cpu
++) {
154 fd
[cpu
][counter
] = sys_perf_event_open(attr
, -1, cpu
, -1, 0);
155 if (fd
[cpu
][counter
] < 0 && verbose
)
156 fprintf(stderr
, ERR_PERF_OPEN
, counter
,
157 fd
[cpu
][counter
], strerror(errno
));
160 attr
->inherit
= inherit
;
162 attr
->enable_on_exec
= 1;
164 fd
[0][counter
] = sys_perf_event_open(attr
, pid
, -1, -1, 0);
165 if (fd
[0][counter
] < 0 && verbose
)
166 fprintf(stderr
, ERR_PERF_OPEN
, counter
,
167 fd
[0][counter
], strerror(errno
));
172 * Does the counter have nsecs as a unit?
174 static inline int nsec_counter(int counter
)
176 if (MATCH_EVENT(SOFTWARE
, SW_CPU_CLOCK
, counter
) ||
177 MATCH_EVENT(SOFTWARE
, SW_TASK_CLOCK
, counter
))
184 * Read out the results of a single counter:
186 static void read_counter(int counter
)
188 u64 count
[3], single_count
[3];
194 count
[0] = count
[1] = count
[2] = 0;
197 for (cpu
= 0; cpu
< nr_cpus
; cpu
++) {
198 if (fd
[cpu
][counter
] < 0)
201 res
= read(fd
[cpu
][counter
], single_count
, nv
* sizeof(u64
));
202 assert(res
== nv
* sizeof(u64
));
204 close(fd
[cpu
][counter
]);
205 fd
[cpu
][counter
] = -1;
207 count
[0] += single_count
[0];
209 count
[1] += single_count
[1];
210 count
[2] += single_count
[2];
217 event_scaled
[counter
] = -1;
222 if (count
[2] < count
[1]) {
223 event_scaled
[counter
] = 1;
224 count
[0] = (unsigned long long)
225 ((double)count
[0] * count
[1] / count
[2] + 0.5);
229 for (i
= 0; i
< 3; i
++)
230 update_stats(&event_res_stats
[counter
][i
], count
[i
]);
233 fprintf(stderr
, "%s: %Ld %Ld %Ld\n", event_name(counter
),
234 count
[0], count
[1], count
[2]);
238 * Save the full runtime - to allow normalization during printout:
240 if (MATCH_EVENT(SOFTWARE
, SW_TASK_CLOCK
, counter
))
241 update_stats(&runtime_nsecs_stats
, count
[0]);
242 if (MATCH_EVENT(HARDWARE
, HW_CPU_CYCLES
, counter
))
243 update_stats(&runtime_cycles_stats
, count
[0]);
244 if (MATCH_EVENT(HARDWARE
, HW_BRANCH_INSTRUCTIONS
, counter
))
245 update_stats(&runtime_branches_stats
, count
[0]);
248 static int run_perf_stat(int argc __used
, const char **argv
)
250 unsigned long long t0
, t1
;
253 int pid
= target_pid
;
254 int child_ready_pipe
[2], go_pipe
[2];
255 const bool forks
= (target_pid
== -1 && argc
> 0);
261 if (forks
&& (pipe(child_ready_pipe
) < 0 || pipe(go_pipe
) < 0)) {
262 perror("failed to create pipes");
267 if ((pid
= fork()) < 0)
268 perror("failed to fork");
271 close(child_ready_pipe
[0]);
273 fcntl(go_pipe
[0], F_SETFD
, FD_CLOEXEC
);
276 * Do a dummy execvp to get the PLT entry resolved,
277 * so we avoid the resolver overhead on the real
280 execvp("", (char **)argv
);
283 * Tell the parent we're ready to go
285 close(child_ready_pipe
[1]);
288 * Wait until the parent tells us to go.
290 if (read(go_pipe
[0], &buf
, 1) == -1)
291 perror("unable to read pipe");
293 execvp(argv
[0], (char **)argv
);
302 * Wait for the child to be ready to exec.
304 close(child_ready_pipe
[1]);
306 if (read(child_ready_pipe
[0], &buf
, 1) == -1)
307 perror("unable to read pipe");
308 close(child_ready_pipe
[0]);
311 for (counter
= 0; counter
< nr_counters
; counter
++)
312 create_perf_stat_counter(counter
, pid
);
315 * Enable counters and exec the command:
328 update_stats(&walltime_nsecs_stats
, t1
- t0
);
330 for (counter
= 0; counter
< nr_counters
; counter
++)
331 read_counter(counter
);
333 return WEXITSTATUS(status
);
336 static void print_noise(int counter
, double avg
)
341 fprintf(stderr
, " ( +- %7.3f%% )",
342 100 * stddev_stats(&event_res_stats
[counter
][0]) / avg
);
345 static void nsec_printout(int counter
, double avg
)
347 double msecs
= avg
/ 1e6
;
349 fprintf(stderr
, " %14.6f %-24s", msecs
, event_name(counter
));
351 if (MATCH_EVENT(SOFTWARE
, SW_TASK_CLOCK
, counter
)) {
352 fprintf(stderr
, " # %10.3f CPUs ",
353 avg
/ avg_stats(&walltime_nsecs_stats
));
357 static void abs_printout(int counter
, double avg
)
359 double total
, ratio
= 0.0;
361 fprintf(stderr
, " %14.0f %-24s", avg
, event_name(counter
));
363 if (MATCH_EVENT(HARDWARE
, HW_INSTRUCTIONS
, counter
)) {
364 total
= avg_stats(&runtime_cycles_stats
);
369 fprintf(stderr
, " # %10.3f IPC ", ratio
);
370 } else if (MATCH_EVENT(HARDWARE
, HW_BRANCH_MISSES
, counter
) &&
371 runtime_branches_stats
.n
!= 0) {
372 total
= avg_stats(&runtime_branches_stats
);
375 ratio
= avg
* 100 / total
;
377 fprintf(stderr
, " # %10.3f %% ", ratio
);
379 } else if (runtime_nsecs_stats
.n
!= 0) {
380 total
= avg_stats(&runtime_nsecs_stats
);
383 ratio
= 1000.0 * avg
/ total
;
385 fprintf(stderr
, " # %10.3f M/sec", ratio
);
390 * Print out the results of a single counter:
392 static void print_counter(int counter
)
394 double avg
= avg_stats(&event_res_stats
[counter
][0]);
395 int scaled
= event_scaled
[counter
];
398 fprintf(stderr
, " %14s %-24s\n",
399 "<not counted>", event_name(counter
));
403 if (nsec_counter(counter
))
404 nsec_printout(counter
, avg
);
406 abs_printout(counter
, avg
);
408 print_noise(counter
, avg
);
411 double avg_enabled
, avg_running
;
413 avg_enabled
= avg_stats(&event_res_stats
[counter
][1]);
414 avg_running
= avg_stats(&event_res_stats
[counter
][2]);
416 fprintf(stderr
, " (scaled from %.2f%%)",
417 100 * avg_running
/ avg_enabled
);
420 fprintf(stderr
, "\n");
423 static void print_stat(int argc
, const char **argv
)
429 fprintf(stderr
, "\n");
430 fprintf(stderr
, " Performance counter stats for ");
431 if(target_pid
== -1) {
432 fprintf(stderr
, "\'%s", argv
[0]);
433 for (i
= 1; i
< argc
; i
++)
434 fprintf(stderr
, " %s", argv
[i
]);
436 fprintf(stderr
, "task pid \'%d", target_pid
);
438 fprintf(stderr
, "\'");
440 fprintf(stderr
, " (%d runs)", run_count
);
441 fprintf(stderr
, ":\n\n");
443 for (counter
= 0; counter
< nr_counters
; counter
++)
444 print_counter(counter
);
446 fprintf(stderr
, "\n");
447 fprintf(stderr
, " %14.9f seconds time elapsed",
448 avg_stats(&walltime_nsecs_stats
)/1e9
);
450 fprintf(stderr
, " ( +- %7.3f%% )",
451 100*stddev_stats(&walltime_nsecs_stats
) /
452 avg_stats(&walltime_nsecs_stats
));
454 fprintf(stderr
, "\n\n");
457 static volatile int signr
= -1;
459 static void skip_signal(int signo
)
467 static void sig_atexit(void)
470 kill(child_pid
, SIGTERM
);
475 signal(signr
, SIG_DFL
);
476 kill(getpid(), signr
);
479 static const char * const stat_usage
[] = {
480 "perf stat [<options>] [<command>]",
484 static const struct option options
[] = {
485 OPT_CALLBACK('e', "event", NULL
, "event",
486 "event selector. use 'perf list' to list available events",
488 OPT_BOOLEAN('i', "inherit", &inherit
,
489 "child tasks inherit counters"),
490 OPT_INTEGER('p', "pid", &target_pid
,
491 "stat events on existing pid"),
492 OPT_BOOLEAN('a', "all-cpus", &system_wide
,
493 "system-wide collection from all CPUs"),
494 OPT_BOOLEAN('c', "scale", &scale
,
495 "scale/normalize counters"),
496 OPT_BOOLEAN('v', "verbose", &verbose
,
497 "be more verbose (show counter open errors, etc)"),
498 OPT_INTEGER('r', "repeat", &run_count
,
499 "repeat command and print average + stddev (max: 100)"),
500 OPT_BOOLEAN('n', "null", &null_run
,
501 "null run - dont start any counters"),
505 int cmd_stat(int argc
, const char **argv
, const char *prefix __used
)
509 argc
= parse_options(argc
, argv
, options
, stat_usage
,
510 PARSE_OPT_STOP_AT_NON_OPTION
);
511 if (!argc
&& target_pid
== -1)
512 usage_with_options(stat_usage
, options
);
514 usage_with_options(stat_usage
, options
);
516 /* Set attrs and nr_counters if no event is selected and !null_run */
517 if (!null_run
&& !nr_counters
) {
518 memcpy(attrs
, default_attrs
, sizeof(default_attrs
));
519 nr_counters
= ARRAY_SIZE(default_attrs
);
522 nr_cpus
= sysconf(_SC_NPROCESSORS_ONLN
);
523 assert(nr_cpus
<= MAX_NR_CPUS
);
524 assert((int)nr_cpus
>= 0);
527 * We dont want to block the signals - that would cause
528 * child tasks to inherit that and Ctrl-C would not work.
529 * What we want is for Ctrl-C to work in the exec()-ed
530 * task, but being ignored by perf stat itself:
533 signal(SIGINT
, skip_signal
);
534 signal(SIGALRM
, skip_signal
);
535 signal(SIGABRT
, skip_signal
);
538 for (run_idx
= 0; run_idx
< run_count
; run_idx
++) {
539 if (run_count
!= 1 && verbose
)
540 fprintf(stderr
, "[ perf stat: executing run #%d ... ]\n", run_idx
+ 1);
541 status
= run_perf_stat(argc
, argv
);
544 print_stat(argc
, argv
);