perf stat: Handle pipe read failures in perf stat
[linux-2.6.git] / tools / perf / builtin-stat.c
1 /*
2  * builtin-stat.c
3  *
4  * Builtin stat command: Give a precise performance counters summary
5  * overview about any workload, CPU or specific PID.
6  *
7  * Sample output:
8
9    $ perf stat ~/hackbench 10
10    Time: 0.104
11
12     Performance counter stats for '/home/mingo/hackbench':
13
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
22
23     Wall-clock time elapsed:   123.786620 msecs
24
25  *
26  * Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com>
27  *
28  * Improvements and fixes by:
29  *
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>
36  *
37  * Released under the GPL v2. (and only v2, not any later version)
38  */
39
40 #include "perf.h"
41 #include "builtin.h"
42 #include "util/util.h"
43 #include "util/parse-options.h"
44 #include "util/parse-events.h"
45
46 #include <sys/prctl.h>
47 #include <math.h>
48
49 static struct perf_counter_attr default_attrs[] = {
50
51   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK      },
52   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES},
53   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_MIGRATIONS  },
54   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS     },
55
56   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES      },
57   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS    },
58   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_REFERENCES},
59   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_MISSES    },
60
61 };
62
63 #define MAX_RUN                 100
64
65 static int                      system_wide                     =  0;
66 static int                      verbose                         =  0;
67 static unsigned int             nr_cpus                         =  0;
68 static int                      run_idx                         =  0;
69
70 static int                      run_count                       =  1;
71 static int                      inherit                         =  1;
72 static int                      scale                           =  1;
73 static int                      target_pid                      = -1;
74 static int                      null_run                        =  0;
75
76 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
77
78 static u64                      runtime_nsecs[MAX_RUN];
79 static u64                      walltime_nsecs[MAX_RUN];
80 static u64                      runtime_cycles[MAX_RUN];
81
82 static u64                      event_res[MAX_RUN][MAX_COUNTERS][3];
83 static u64                      event_scaled[MAX_RUN][MAX_COUNTERS];
84
85 static u64                      event_res_avg[MAX_COUNTERS][3];
86 static u64                      event_res_noise[MAX_COUNTERS][3];
87
88 static u64                      event_scaled_avg[MAX_COUNTERS];
89
90 static u64                      runtime_nsecs_avg;
91 static u64                      runtime_nsecs_noise;
92
93 static u64                      walltime_nsecs_avg;
94 static u64                      walltime_nsecs_noise;
95
96 static u64                      runtime_cycles_avg;
97 static u64                      runtime_cycles_noise;
98
99 #define MATCH_EVENT(t, c, counter)                      \
100         (attrs[counter].type == PERF_TYPE_##t &&        \
101          attrs[counter].config == PERF_COUNT_##c)
102
103 #define ERR_PERF_OPEN \
104 "Error: counter %d, sys_perf_counter_open() syscall returned with %d (%s)\n"
105
106 static void create_perf_stat_counter(int counter, int pid)
107 {
108         struct perf_counter_attr *attr = attrs + counter;
109
110         if (scale)
111                 attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
112                                     PERF_FORMAT_TOTAL_TIME_RUNNING;
113
114         if (system_wide) {
115                 unsigned int cpu;
116
117                 for (cpu = 0; cpu < nr_cpus; cpu++) {
118                         fd[cpu][counter] = sys_perf_counter_open(attr, -1, cpu, -1, 0);
119                         if (fd[cpu][counter] < 0 && verbose)
120                                 fprintf(stderr, ERR_PERF_OPEN, counter,
121                                         fd[cpu][counter], strerror(errno));
122                 }
123         } else {
124                 attr->inherit        = inherit;
125                 attr->disabled       = 1;
126                 attr->enable_on_exec = 1;
127
128                 fd[0][counter] = sys_perf_counter_open(attr, pid, -1, -1, 0);
129                 if (fd[0][counter] < 0 && verbose)
130                         fprintf(stderr, ERR_PERF_OPEN, counter,
131                                 fd[0][counter], strerror(errno));
132         }
133 }
134
135 /*
136  * Does the counter have nsecs as a unit?
137  */
138 static inline int nsec_counter(int counter)
139 {
140         if (MATCH_EVENT(SOFTWARE, SW_CPU_CLOCK, counter) ||
141             MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
142                 return 1;
143
144         return 0;
145 }
146
147 /*
148  * Read out the results of a single counter:
149  */
150 static void read_counter(int counter)
151 {
152         u64 *count, single_count[3];
153         unsigned int cpu;
154         size_t res, nv;
155         int scaled;
156
157         count = event_res[run_idx][counter];
158
159         count[0] = count[1] = count[2] = 0;
160
161         nv = scale ? 3 : 1;
162         for (cpu = 0; cpu < nr_cpus; cpu++) {
163                 if (fd[cpu][counter] < 0)
164                         continue;
165
166                 res = read(fd[cpu][counter], single_count, nv * sizeof(u64));
167                 assert(res == nv * sizeof(u64));
168
169                 close(fd[cpu][counter]);
170                 fd[cpu][counter] = -1;
171
172                 count[0] += single_count[0];
173                 if (scale) {
174                         count[1] += single_count[1];
175                         count[2] += single_count[2];
176                 }
177         }
178
179         scaled = 0;
180         if (scale) {
181                 if (count[2] == 0) {
182                         event_scaled[run_idx][counter] = -1;
183                         count[0] = 0;
184                         return;
185                 }
186
187                 if (count[2] < count[1]) {
188                         event_scaled[run_idx][counter] = 1;
189                         count[0] = (unsigned long long)
190                                 ((double)count[0] * count[1] / count[2] + 0.5);
191                 }
192         }
193         /*
194          * Save the full runtime - to allow normalization during printout:
195          */
196         if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
197                 runtime_nsecs[run_idx] = count[0];
198         if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter))
199                 runtime_cycles[run_idx] = count[0];
200 }
201
202 static int run_perf_stat(int argc __used, const char **argv)
203 {
204         unsigned long long t0, t1;
205         int status = 0;
206         int counter;
207         int pid;
208         int child_ready_pipe[2], go_pipe[2];
209         char buf;
210
211         if (!system_wide)
212                 nr_cpus = 1;
213
214         if (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0) {
215                 perror("failed to create pipes");
216                 exit(1);
217         }
218
219         if ((pid = fork()) < 0)
220                 perror("failed to fork");
221
222         if (!pid) {
223                 close(child_ready_pipe[0]);
224                 close(go_pipe[1]);
225                 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
226
227                 /*
228                  * Do a dummy execvp to get the PLT entry resolved,
229                  * so we avoid the resolver overhead on the real
230                  * execvp call.
231                  */
232                 execvp("", (char **)argv);
233
234                 /*
235                  * Tell the parent we're ready to go
236                  */
237                 close(child_ready_pipe[1]);
238
239                 /*
240                  * Wait until the parent tells us to go.
241                  */
242                 if (read(go_pipe[0], &buf, 1) == -1)
243                         perror("unable to read pipe");
244
245                 execvp(argv[0], (char **)argv);
246
247                 perror(argv[0]);
248                 exit(-1);
249         }
250
251         /*
252          * Wait for the child to be ready to exec.
253          */
254         close(child_ready_pipe[1]);
255         close(go_pipe[0]);
256         if (read(child_ready_pipe[0], &buf, 1) == -1)
257                 perror("unable to read pipe");
258         close(child_ready_pipe[0]);
259
260         for (counter = 0; counter < nr_counters; counter++)
261                 create_perf_stat_counter(counter, pid);
262
263         /*
264          * Enable counters and exec the command:
265          */
266         t0 = rdclock();
267
268         close(go_pipe[1]);
269         wait(&status);
270
271         t1 = rdclock();
272
273         walltime_nsecs[run_idx] = t1 - t0;
274
275         for (counter = 0; counter < nr_counters; counter++)
276                 read_counter(counter);
277
278         return WEXITSTATUS(status);
279 }
280
281 static void print_noise(u64 *count, u64 *noise)
282 {
283         if (run_count > 1)
284                 fprintf(stderr, "   ( +- %7.3f%% )",
285                         (double)noise[0]/(count[0]+1)*100.0);
286 }
287
288 static void nsec_printout(int counter, u64 *count, u64 *noise)
289 {
290         double msecs = (double)count[0] / 1000000;
291
292         fprintf(stderr, " %14.6f  %-24s", msecs, event_name(counter));
293
294         if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) {
295                 if (walltime_nsecs_avg)
296                         fprintf(stderr, " # %10.3f CPUs ",
297                                 (double)count[0] / (double)walltime_nsecs_avg);
298         }
299         print_noise(count, noise);
300 }
301
302 static void abs_printout(int counter, u64 *count, u64 *noise)
303 {
304         fprintf(stderr, " %14Ld  %-24s", count[0], event_name(counter));
305
306         if (runtime_cycles_avg &&
307             MATCH_EVENT(HARDWARE, HW_INSTRUCTIONS, counter)) {
308                 fprintf(stderr, " # %10.3f IPC  ",
309                         (double)count[0] / (double)runtime_cycles_avg);
310         } else {
311                 if (runtime_nsecs_avg) {
312                         fprintf(stderr, " # %10.3f M/sec",
313                                 (double)count[0]/runtime_nsecs_avg*1000.0);
314                 }
315         }
316         print_noise(count, noise);
317 }
318
319 /*
320  * Print out the results of a single counter:
321  */
322 static void print_counter(int counter)
323 {
324         u64 *count, *noise;
325         int scaled;
326
327         count = event_res_avg[counter];
328         noise = event_res_noise[counter];
329         scaled = event_scaled_avg[counter];
330
331         if (scaled == -1) {
332                 fprintf(stderr, " %14s  %-24s\n",
333                         "<not counted>", event_name(counter));
334                 return;
335         }
336
337         if (nsec_counter(counter))
338                 nsec_printout(counter, count, noise);
339         else
340                 abs_printout(counter, count, noise);
341
342         if (scaled)
343                 fprintf(stderr, "  (scaled from %.2f%%)",
344                         (double) count[2] / count[1] * 100);
345
346         fprintf(stderr, "\n");
347 }
348
349 /*
350  * normalize_noise noise values down to stddev:
351  */
352 static void normalize_noise(u64 *val)
353 {
354         double res;
355
356         res = (double)*val / (run_count * sqrt((double)run_count));
357
358         *val = (u64)res;
359 }
360
361 static void update_avg(const char *name, int idx, u64 *avg, u64 *val)
362 {
363         *avg += *val;
364
365         if (verbose > 1)
366                 fprintf(stderr, "debug: %20s[%d]: %Ld\n", name, idx, *val);
367 }
368 /*
369  * Calculate the averages and noises:
370  */
371 static void calc_avg(void)
372 {
373         int i, j;
374
375         if (verbose > 1)
376                 fprintf(stderr, "\n");
377
378         for (i = 0; i < run_count; i++) {
379                 update_avg("runtime", 0, &runtime_nsecs_avg, runtime_nsecs + i);
380                 update_avg("walltime", 0, &walltime_nsecs_avg, walltime_nsecs + i);
381                 update_avg("runtime_cycles", 0, &runtime_cycles_avg, runtime_cycles + i);
382
383                 for (j = 0; j < nr_counters; j++) {
384                         update_avg("counter/0", j,
385                                 event_res_avg[j]+0, event_res[i][j]+0);
386                         update_avg("counter/1", j,
387                                 event_res_avg[j]+1, event_res[i][j]+1);
388                         update_avg("counter/2", j,
389                                 event_res_avg[j]+2, event_res[i][j]+2);
390                         if (event_scaled[i][j] != (u64)-1)
391                                 update_avg("scaled", j,
392                                         event_scaled_avg + j, event_scaled[i]+j);
393                         else
394                                 event_scaled_avg[j] = -1;
395                 }
396         }
397         runtime_nsecs_avg /= run_count;
398         walltime_nsecs_avg /= run_count;
399         runtime_cycles_avg /= run_count;
400
401         for (j = 0; j < nr_counters; j++) {
402                 event_res_avg[j][0] /= run_count;
403                 event_res_avg[j][1] /= run_count;
404                 event_res_avg[j][2] /= run_count;
405         }
406
407         for (i = 0; i < run_count; i++) {
408                 runtime_nsecs_noise +=
409                         abs((s64)(runtime_nsecs[i] - runtime_nsecs_avg));
410                 walltime_nsecs_noise +=
411                         abs((s64)(walltime_nsecs[i] - walltime_nsecs_avg));
412                 runtime_cycles_noise +=
413                         abs((s64)(runtime_cycles[i] - runtime_cycles_avg));
414
415                 for (j = 0; j < nr_counters; j++) {
416                         event_res_noise[j][0] +=
417                                 abs((s64)(event_res[i][j][0] - event_res_avg[j][0]));
418                         event_res_noise[j][1] +=
419                                 abs((s64)(event_res[i][j][1] - event_res_avg[j][1]));
420                         event_res_noise[j][2] +=
421                                 abs((s64)(event_res[i][j][2] - event_res_avg[j][2]));
422                 }
423         }
424
425         normalize_noise(&runtime_nsecs_noise);
426         normalize_noise(&walltime_nsecs_noise);
427         normalize_noise(&runtime_cycles_noise);
428
429         for (j = 0; j < nr_counters; j++) {
430                 normalize_noise(&event_res_noise[j][0]);
431                 normalize_noise(&event_res_noise[j][1]);
432                 normalize_noise(&event_res_noise[j][2]);
433         }
434 }
435
436 static void print_stat(int argc, const char **argv)
437 {
438         int i, counter;
439
440         calc_avg();
441
442         fflush(stdout);
443
444         fprintf(stderr, "\n");
445         fprintf(stderr, " Performance counter stats for \'%s", argv[0]);
446
447         for (i = 1; i < argc; i++)
448                 fprintf(stderr, " %s", argv[i]);
449
450         fprintf(stderr, "\'");
451         if (run_count > 1)
452                 fprintf(stderr, " (%d runs)", run_count);
453         fprintf(stderr, ":\n\n");
454
455         for (counter = 0; counter < nr_counters; counter++)
456                 print_counter(counter);
457
458         fprintf(stderr, "\n");
459         fprintf(stderr, " %14.9f  seconds time elapsed",
460                         (double)walltime_nsecs_avg/1e9);
461         if (run_count > 1) {
462                 fprintf(stderr, "   ( +- %7.3f%% )",
463                         100.0*(double)walltime_nsecs_noise/(double)walltime_nsecs_avg);
464         }
465         fprintf(stderr, "\n\n");
466 }
467
468 static volatile int signr = -1;
469
470 static void skip_signal(int signo)
471 {
472         signr = signo;
473 }
474
475 static void sig_atexit(void)
476 {
477         if (signr == -1)
478                 return;
479
480         signal(signr, SIG_DFL);
481         kill(getpid(), signr);
482 }
483
484 static const char * const stat_usage[] = {
485         "perf stat [<options>] <command>",
486         NULL
487 };
488
489 static const struct option options[] = {
490         OPT_CALLBACK('e', "event", NULL, "event",
491                      "event selector. use 'perf list' to list available events",
492                      parse_events),
493         OPT_BOOLEAN('i', "inherit", &inherit,
494                     "child tasks inherit counters"),
495         OPT_INTEGER('p', "pid", &target_pid,
496                     "stat events on existing pid"),
497         OPT_BOOLEAN('a', "all-cpus", &system_wide,
498                     "system-wide collection from all CPUs"),
499         OPT_BOOLEAN('S', "scale", &scale,
500                     "scale/normalize counters"),
501         OPT_BOOLEAN('v', "verbose", &verbose,
502                     "be more verbose (show counter open errors, etc)"),
503         OPT_INTEGER('r', "repeat", &run_count,
504                     "repeat command and print average + stddev (max: 100)"),
505         OPT_BOOLEAN('n', "null", &null_run,
506                     "null run - dont start any counters"),
507         OPT_END()
508 };
509
510 int cmd_stat(int argc, const char **argv, const char *prefix __used)
511 {
512         int status;
513
514         argc = parse_options(argc, argv, options, stat_usage, 0);
515         if (!argc)
516                 usage_with_options(stat_usage, options);
517         if (run_count <= 0 || run_count > MAX_RUN)
518                 usage_with_options(stat_usage, options);
519
520         /* Set attrs and nr_counters if no event is selected and !null_run */
521         if (!null_run && !nr_counters) {
522                 memcpy(attrs, default_attrs, sizeof(default_attrs));
523                 nr_counters = ARRAY_SIZE(default_attrs);
524         }
525
526         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
527         assert(nr_cpus <= MAX_NR_CPUS);
528         assert((int)nr_cpus >= 0);
529
530         /*
531          * We dont want to block the signals - that would cause
532          * child tasks to inherit that and Ctrl-C would not work.
533          * What we want is for Ctrl-C to work in the exec()-ed
534          * task, but being ignored by perf stat itself:
535          */
536         atexit(sig_atexit);
537         signal(SIGINT,  skip_signal);
538         signal(SIGALRM, skip_signal);
539         signal(SIGABRT, skip_signal);
540
541         status = 0;
542         for (run_idx = 0; run_idx < run_count; run_idx++) {
543                 if (run_count != 1 && verbose)
544                         fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1);
545                 status = run_perf_stat(argc, argv);
546         }
547
548         print_stat(argc, argv);
549
550         return status;
551 }