aboutsummaryrefslogtreecommitdiffstats
path: root/tools/perf/builtin-record.c
blob: 0f467cf7aa72f022a75eadbe493b839f9e93f6fa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
/*
 * builtin-record.c
 *
 * Builtin record command: Record the profile of a workload
 * (or a CPU, or a PID) into the perf.data output file - for
 * later analysis via perf report.
 */
#define _FILE_OFFSET_BITS 64

#include "builtin.h"

#include "perf.h"

#include "util/build-id.h"
#include "util/util.h"
#include "util/parse-options.h"
#include "util/parse-events.h"

#include "util/header.h"
#include "util/event.h"
#include "util/debug.h"
#include "util/session.h"
#include "util/symbol.h"
#include "util/cpumap.h"

#include <unistd.h>
#include <sched.h>

enum write_mode_t {
	WRITE_FORCE,
	WRITE_APPEND
};

static int			*fd[MAX_NR_CPUS][MAX_COUNTERS];

static unsigned int		user_interval 			= UINT_MAX;
static long			default_interval		=      0;

static int			nr_cpus				=      0;
static unsigned int		page_size;
static unsigned int		mmap_pages			=    128;
static unsigned int		user_freq 			= UINT_MAX;
static int			freq				=   1000;
static int			output;
static int			pipe_output			=      0;
static const char		*output_name			= "perf.data";
static int			group				=      0;
static unsigned int		realtime_prio			=      0;
static bool			raw_samples			=  false;
static bool			system_wide			=  false;
static int			profile_cpu			=     -1;
static pid_t			target_pid			=     -1;
static pid_t			target_tid			=     -1;
static pid_t			*all_tids			=      NULL;
static int			thread_num			=      0;
static pid_t			child_pid			=     -1;
static bool			no_inherit			=  false;
static enum write_mode_t	write_mode			= WRITE_FORCE;
static bool			call_graph			=  false;
static bool			inherit_stat			=  false;
static bool			no_samples			=  false;
static bool			sample_address			=  false;
static bool			multiplex			=  false;
static int			multiplex_fd			=     -1;

static long			samples				=      0;
static struct timeval		last_read;
static struct timeval		this_read;

static u64			bytes_written			=      0;

static struct pollfd		*event_array;

static int			nr_poll				=      0;
static int			nr_cpu				=      0;

static int			file_new			=      1;
static off_t			post_processing_offset;

static struct perf_session	*session;

struct mmap_data {
	int			counter;
	void			*base;
	unsigned int		mask;
	unsigned int		prev;
};

static struct mmap_data		*mmap_array[MAX_NR_CPUS][MAX_COUNTERS];

static unsigned long mmap_read_head(struct mmap_data *md)
{
	struct perf_event_mmap_page *pc = md->base;
	long head;

	head = pc->data_head;
	rmb();

	return head;
}

static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
{
	struct perf_event_mmap_page *pc = md->base;

	/*
	 * ensure all reads are done before we write the tail out.
	 */
	/* mb(); */
	pc->data_tail = tail;
}

static void advance_output(size_t size)
{
	bytes_written += size;
}

static void write_output(void *buf, size_t size)
{
	while (size) {
		int ret = write(output, buf, size);

		if (ret < 0)
			die("failed to write");

		size -= ret;
		buf += ret;

		bytes_written += ret;
	}
}

static int process_synthesized_event(event_t *event,
				     struct perf_session *self __used)
{
	write_output(event, event->header.size);
	return 0;
}

static void mmap_read(struct mmap_data *md)
{
	unsigned int head = mmap_read_head(md);
	unsigned int old = md->prev;
	unsigned char *data = md->base + page_size;
	unsigned long size;
	void *buf;
	int diff;

	gettimeofday(&this_read, NULL);

	/*
	 * If we're further behind than half the buffer, there's a chance
	 * the writer will bite our tail and mess up the samples under us.
	 *
	 * If we somehow ended up ahead of the head, we got messed up.
	 *
	 * In either case, truncate and restart at head.
	 */
	diff = head - old;
	if (diff < 0) {
		struct timeval iv;
		unsigned long msecs;

		timersub(&this_read, &last_read, &iv);
		msecs = iv.tv_sec*1000 + iv.tv_usec/1000;

		fprintf(stderr, "WARNING: failed to keep up with mmap data."
				"  Last read %lu msecs ago.\n", msecs);

		/*
		 * head points to a known good entry, start there.
		 */
		old = head;
	}

	last_read = this_read;

	if (old != head)
		samples++;

	size = head - old;

	if ((old & md->mask) + size != (head & md->mask)) {
		buf = &data[old & md->mask];
		size = md->mask + 1 - (old & md->mask);
		old += size;

		write_output(buf, size);
	}

	buf = &data[old & md->mask];
	size = head - old;
	old += size;

	write_output(buf, size);

	md->prev = old;
	mmap_write_tail(md, old);
}

static volatile int done = 0;
static volatile int signr = -1;

static void sig_handler(int sig)
{
	done = 1;
	signr = sig;
}

static void sig_atexit(void)
{
	if (child_pid != -1)
		kill(child_pid, SIGTERM);

	if (signr == -1)
		return;

	signal(signr, SIG_DFL);
	kill(getpid(), signr);
}

static int group_fd;

static struct perf_header_attr *get_header_attr(struct perf_event_attr *a, int nr)
{
	struct perf_header_attr *h_attr;

	if (nr < session->header.attrs) {
		h_attr = session->header.attr[nr];
	} else {
		h_attr = perf_header_attr__new(a);
		if (h_attr != NULL)
			if (perf_header__add_attr(&session->header, h_attr) < 0) {
				perf_header_attr__delete(h_attr);
				h_attr = NULL;
			}
	}

	return h_attr;
}

static void create_counter(int counter, int cpu)
{
	char *filter = filters[counter];
	struct perf_event_attr *attr = attrs + counter;
	struct perf_header_attr *h_attr;
	int track = !counter; /* only the first counter needs these */
	int thread_index;
	int ret;
	struct {
		u64 count;
		u64 time_enabled;
		u64 time_running;
		u64 id;
	} read_data;

	attr->read_format	= PERF_FORMAT_TOTAL_TIME_ENABLED |
				  PERF_FORMAT_TOTAL_TIME_RUNNING |
				  PERF_FORMAT_ID;

	attr->sample_type	|= PERF_SAMPLE_IP | PERF_SAMPLE_TID;

	if (nr_counters > 1)
		attr->sample_type |= PERF_SAMPLE_ID;

	/*
	 * We default some events to a 1 default interval. But keep
	 * it a weak assumption overridable by the user.
	 */
	if (!attr->sample_period || (user_freq != UINT_MAX &&
				     user_interval != UINT_MAX)) {
		if (freq) {
			attr->sample_type	|= PERF_SAMPLE_PERIOD;
			attr->freq		= 1;
			attr->sample_freq	= freq;
		} else {
			attr->sample_period = default_interval;
		}
	}

	if (no_samples)
		attr->sample_freq = 0;

	if (inherit_stat)
		attr->inherit_stat = 1;

	if (sample_address)
		attr->sample_type	|= PERF_SAMPLE_ADDR;

	if (call_graph)
		attr->sample_type	|= PERF_SAMPLE_CALLCHAIN;

	if (raw_samples) {
		attr->sample_type	|= PERF_SAMPLE_TIME;
		attr->sample_type	|= PERF_SAMPLE_RAW;
		attr->sample_type	|= PERF_SAMPLE_CPU;
	}

	attr->mmap		= track;
	attr->comm		= track;
	attr->inherit		= !no_inherit;
	if (target_pid == -1 && target_tid == -1 && !system_wide) {
		attr->disabled = 1;
		attr->enable_on_exec = 1;
	}

	for (thread_index = 0; thread_index < thread_num; thread_index++) {
try_again:
		fd[nr_cpu][counter][thread_index] = sys_perf_event_open(attr,
				all_tids[thread_index], cpu, group_fd, 0);

		if (fd[nr_cpu][counter][thread_index] < 0) {
			int err = errno;

			if (err == EPERM || err == EACCES)
				die("Permission error - are you root?\n"
					"\t Consider tweaking"
					" /proc/sys/kernel/perf_event_paranoid.\n");
			else if (err ==  ENODEV && profile_cpu != -1) {
				die("No such device - did you specify"
					" an out-of-range profile CPU?\n");
			}

			/*
			 * If it's cycles then fall back to hrtimer
			 * based cpu-clock-tick sw counter, which
			 * is always available even if no PMU support:
			 */
			if (attr->type == PERF_TYPE_HARDWARE
					&& attr->config == PERF_COUNT_HW_CPU_CYCLES) {

				if (verbose)
					warning(" ... trying to fall back to cpu-clock-ticks\n");
				attr->type = PERF_TYPE_SOFTWARE;
				attr->config = PERF_COUNT_SW_CPU_CLOCK;
				goto try_again;
			}
			printf("\n");
			error("perfcounter syscall returned with %d (%s)\n",
					fd[nr_cpu][counter][thread_index], strerror(err));

#if defined(__i386__) || defined(__x86_64__)
			if (attr->type == PERF_TYPE_HARDWARE && err == EOPNOTSUPP)
				die("No hardware sampling interrupt available."
				    " No APIC? If so then you can boot the kernel"
				    " with the \"lapic\" boot parameter to"
				    " force-enable it.\n");
#endif

			die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
			exit(-1);
		}

		h_attr = get_header_attr(attr, counter);
		if (h_attr == NULL)
			die("nomem\n");

		if (!file_new) {
			if (memcmp(&h_attr->attr, attr, sizeof(*attr))) {
				fprintf(stderr, "incompatible append\n");
				exit(-1);
			}
		}

		if (read(fd[nr_cpu][counter][thread_index], &read_data, sizeof(read_data)) == -1) {
			perror("Unable to read perf file descriptor\n");
			exit(-1);
		}

		if (perf_header_attr__add_id(h_attr, read_data.id) < 0) {
			pr_warning("Not enough memory to add id\n");
			exit(-1);
		}

		assert(fd[nr_cpu][counter][thread_index] >= 0);
		fcntl(fd[nr_cpu][counter][thread_index], F_SETFL, O_NONBLOCK);

		/*
		 * First counter acts as the group leader:
		 */
		if (group && group_fd == -1)
			group_fd = fd[nr_cpu][counter][thread_index];
		if (multiplex && multiplex_fd == -1)
			multiplex_fd = fd[nr_cpu][counter][thread_index];

		if (multiplex && fd[nr_cpu][counter][thread_index] != multiplex_fd) {

			ret = ioctl(fd[nr_cpu][counter][thread_index], PERF_EVENT_IOC_SET_OUTPUT, multiplex_fd);
			assert(ret != -1);
		} else {
			event_array[nr_poll].fd = fd[nr_cpu][counter][thread_index];
			event_array[nr_poll].events = POLLIN;
			nr_poll++;

			mmap_array[nr_cpu][counter][thread_index].counter = counter;
			mmap_array[nr_cpu][counter][thread_index].prev = 0;
			mmap_array[nr_cpu][counter][thread_index].mask = mmap_pages*page_size - 1;
			mmap_array[nr_cpu][counter][thread_index].base = mmap(NULL, (mmap_pages+1)*page_size,
				PROT_READ|PROT_WRITE, MAP_SHARED, fd[nr_cpu][counter][thread_index], 0);
			if (mmap_array[nr_cpu][counter][thread_index].base == MAP_FAILED) {
				error("failed to mmap with %d (%s)\n", errno, strerror(errno));
				exit(-1);
			}
		}

		if (filter != NULL) {
			ret = ioctl(fd[nr_cpu][counter][thread_index],
					PERF_EVENT_IOC_SET_FILTER, filter);
			if (ret) {
				error("failed to set filter with %d (%s)\n", errno,
						strerror(errno));
				exit(-1);
			}
		}
	}
}

static void open_counters(int cpu)
{
	int counter;

	group_fd = -1;
	for (counter = 0; counter < nr_counters; counter++)
		create_counter(counter, cpu);

	nr_cpu++;
}

static int process_buildids(void)
{
	u64 size = lseek(output, 0, SEEK_CUR);

	if (size == 0)
		return 0;

	session->fd = output;
	return __perf_session__process_events(session, post_processing_offset,
					      size - post_processing_offset,
					      size, &build_id__mark_dso_hit_ops);
}

static void atexit_header(void)
{
	if (!pipe_output) {
		session->header.data_size += bytes_written;

		process_buildids();
		perf_header__write(&session->header, output, true);
	}
}

static void event__synthesize_guest_os(struct machine *machine, void *data)
{
	int err;
	char *guest_kallsyms;
	char path[PATH_MAX];
	struct perf_session *psession = data;

	if (machine__is_host(machine))
		return;

	/*
	 *As for guest kernel when processing subcommand record&report,
	 *we arrange module mmap prior to guest kernel mmap and trigger
	 *a preload dso because default guest module symbols are loaded
	 *from guest kallsyms instead of /lib/modules/XXX/XXX. This
	 *method is used to avoid symbol missing when the first addr is
	 *in module instead of in guest kernel.
	 */
	err = event__synthesize_modules(process_synthesized_event,
					psession, machine);
	if (err < 0)
		pr_err("Couldn't record guest kernel [%d]'s reference"
		       " relocation symbol.\n", machine->pid);

	if (machine__is_default_guest(machine))
		guest_kallsyms = (char *) symbol_conf.default_guest_kallsyms;
	else {
		sprintf(path, "%s/proc/kallsyms", machine->root_dir);
		guest_kallsyms = path;
	}

	/*
	 * We use _stext for guest kernel because guest kernel's /proc/kallsyms
	 * have no _text sometimes.
	 */
	err = event__synthesize_kernel_mmap(process_synthesized_event,
					    psession, machine, "_text");
	if (err < 0)
		err = event__synthesize_kernel_mmap(process_synthesized_event,
						    psession, machine, "_stext");
	if (err < 0)
		pr_err("Couldn't record guest kernel [%d]'s reference"
		       " relocation symbol.\n", machine->pid);
}

static struct perf_event_header finished_round_event = {
	.size = sizeof(struct perf_event_header),
	.type = PERF_RECORD_FINISHED_ROUND,
};

static void mmap_read_all(void)
{
	int i, counter, thread;

	for (i = 0; i < nr_cpu; i++) {
		for (counter = 0; counter < nr_counters; counter++) {
			for (thread = 0; thread < thread_num; thread++) {
				if (mmap_array[i][counter][thread].base)
					mmap_read(&mmap_array[i][counter][thread]);
			}

		}
	}

	if (perf_header__has_feat(&session->header, HEADER_TRACE_INFO))
		write_output(&finished_round_event, sizeof(finished_round_event));
}

static int __cmd_record(int argc, const char **argv)
{
	int i, counter;
	struct stat st;
	pid_t pid = 0;
	int flags;
	int err;
	unsigned long waking = 0;
	int child_ready_pipe[2], go_pipe[2];
	const bool forks = argc > 0;
	char buf;
	struct machine *machine;

	page_size = sysconf(_SC_PAGE_SIZE);

	atexit(sig_atexit);
	signal(SIGCHLD, sig_handler);
	signal(SIGINT, sig_handler);

	if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
		perror("failed to create pipes");
		exit(-1);
	}

	if (!strcmp(output_name, "-"))
		pipe_output = 1;
	else if (!stat(output_name, &st) && st.st_size) {
		if (write_mode == WRITE_FORCE) {
			char oldname[PATH_MAX];
			snprintf(oldname, sizeof(oldname), "%s.old",
				 output_name);
			unlink(oldname);
			rename(output_name, oldname);
		}
	} else if (write_mode == WRITE_APPEND) {
		write_mode = WRITE_FORCE;
	}

	flags = O_CREAT|O_RDWR;
	if (write_mode == WRITE_APPEND)
		file_new = 0;
	else
		flags |= O_TRUNC;

	if (pipe_output)
		output = STDOUT_FILENO;
	else
		output = open(output_name, flags, S_IRUSR | S_IWUSR);
	if (output < 0) {
		perror("failed to create output file");
		exit(-1);
	}

	session = perf_session__new(output_name, O_WRONLY,
				    write_mode == WRITE_FORCE, false);
	if (session == NULL) {
		pr_err("Not enough memory for reading perf file header\n");
		return -1;
	}

	if (!file_new) {
		err = perf_header__read(session, output);
		if (err < 0)
			return err;
	}

	if (have_tracepoints(attrs, nr_counters))
		perf_header__set_feat(&session->header, HEADER_TRACE_INFO);

	atexit(atexit_header);

	if (forks) {
		child_pid = fork();
		if (pid < 0) {
			perror("failed to fork");
			exit(-1);
		}

		if (!child_pid) {
			if (pipe_output)
				dup2(2, 1);
			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);
		}

		if (!system_wide && target_tid == -1 && target_pid == -1)
			all_tids[0] = child_pid;

		close(child_ready_pipe[1]);
		close(go_pipe[0]);
		/*
		 * wait for child to settle
		 */
		if (read(child_ready_pipe[0], &buf, 1) == -1) {
			perror("unable to read pipe");
			exit(-1);
		}
		close(child_ready_pipe[0]);
	}

	if ((!system_wide && no_inherit) || profile_cpu != -1) {
		open_counters(profile_cpu);
	} else {
		nr_cpus = read_cpu_map();
		for (i = 0; i < nr_cpus; i++)
			open_counters(cpumap[i]);
	}

	if (pipe_output) {
		err = perf_header__write_pipe(output);
		if (err < 0)
			return err;
	} else if (file_new) {
		err = perf_header__write(&session->header, output, false);
		if (err < 0)
			return err;
	}

	post_processing_offset = lseek(output, 0, SEEK_CUR);

	if (pipe_output) {
		err = event__synthesize_attrs(&session->header,
					      process_synthesized_event,
					      session);
		if (err < 0) {
			pr_err("Couldn't synthesize attrs.\n");
			return err;
		}

		err = event__synthesize_event_types(process_synthesized_event,
						    session);
		if (err < 0) {
			pr_err("Couldn't synthesize event_types.\n");
			return err;
		}

		if (have_tracepoints(attrs, nr_counters)) {
			/*
			 * FIXME err <= 0 here actually means that
			 * there were no tracepoints so its not really
			 * an error, just that we don't need to
			 * synthesize anything.  We really have to
			 * return this more properly and also
			 * propagate errors that now are calling die()
			 */
			err = event__synthesize_tracing_data(output, attrs,
							     nr_counters,
							     process_synthesized_event,
							     session);
			if (err <= 0) {
				pr_err("Couldn't record tracing data.\n");
				return err;
			}
			advance_output(err);
		}
	}

	machine = perf_session__find_host_machine(session);
	if (!machine) {
		pr_err("Couldn't find native kernel information.\n");
		return -1;
	}

	err = event__synthesize_kernel_mmap(process_synthesized_event,
					    session, machine, "_text");
	if (err < 0)
		err = event__synthesize_kernel_mmap(process_synthesized_event,
						    session, machine, "_stext");
	if (err < 0) {
		pr_err("Couldn't record kernel reference relocation symbol.\n");
		return err;
	}

	err = event__synthesize_modules(process_synthesized_event,
					session, machine);
	if (err < 0) {
		pr_err("Couldn't record kernel reference relocation symbol.\n");
		return err;
	}
	if (perf_guest)
		perf_session__process_machines(session, event__synthesize_guest_os);

	if (!system_wide && profile_cpu == -1)
		event__synthesize_thread(target_tid, process_synthesized_event,
					 session);
	else
		event__synthesize_threads(process_synthesized_event, session);

	if (realtime_prio) {
		struct sched_param param;

		param.sched_priority = realtime_prio;
		if (sched_setscheduler(0, SCHED_FIFO, &param)) {
			pr_err("Could not set realtime priority.\n");
			exit(-1);
		}
	}

	/*
	 * Let the child rip
	 */
	if (forks)
		close(go_pipe[1]);

	for (;;) {
		int hits = samples;
		int thread;

		mmap_read_all();

		if (hits == samples) {
			if (done)
				break;
			err = poll(event_array, nr_poll, -1);
			waking++;
		}

		if (done) {
			for (i = 0; i < nr_cpu; i++) {
				for (counter = 0;
					counter < nr_counters;
					counter++) {
					for (thread = 0;
						thread < thread_num;
						thread++)
						ioctl(fd[i][counter][thread],
							PERF_EVENT_IOC_DISABLE);
				}
			}
		}
	}

	fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);

	/*
	 * Approximate RIP event size: 24 bytes.
	 */
	fprintf(stderr,
		"[ perf record: Captured and wrote %.3f MB %s (~%lld samples) ]\n",
		(double)bytes_written / 1024.0 / 1024.0,
		output_name,
		bytes_written / 24);

	return 0;
}

static const char * const record_usage[] = {
	"perf record [<options>] [<command>]",
	"perf record [<options>] -- <command> [<options>]",
	NULL
};

static bool force, append_file;

static const struct option options[] = {
	OPT_CALLBACK('e', "event", NULL, "event",
		     "event selector. use 'perf list' to list available events",
		     parse_events),
	OPT_CALLBACK(0, "filter", NULL, "filter",
		     "event filter", parse_filter),
	OPT_INTEGER('p', "pid", &target_pid,
		    "record events on existing process id"),
	OPT_INTEGER('t', "tid", &target_tid,
		    "record events on existing thread id"),
	OPT_INTEGER('r', "realtime", &realtime_prio,
		    "collect data with this RT SCHED_FIFO priority"),
	OPT_BOOLEAN('R', "raw-samples", &raw_samples,
		    "collect raw sample records from all opened counters"),
	OPT_BOOLEAN('a', "all-cpus", &system_wide,
			    "system-wide collection from all CPUs"),
	OPT_BOOLEAN('A', "append", &append_file,
			    "append to the output file to do incremental profiling"),
	OPT_INTEGER('C', "profile_cpu", &profile_cpu,
			    "CPU to profile on"),
	OPT_BOOLEAN('f', "force", &force,
			"overwrite existing data file (deprecated)"),
	OPT_LONG('c', "count", &user_interval,
		    "event period to sample"),
	OPT_STRING('o', "output", &output_name, "file",
		    "output file name"),
	OPT_BOOLEAN('i', "no-inherit", &no_inherit,
		    "child tasks do not inherit counters"),
	OPT_INTEGER('F', "freq", &user_freq,
		    "profile at this frequency"),
	OPT_INTEGER('m', "mmap-pages", &mmap_pages,
		    "number of mmap data pages"),
	OPT_BOOLEAN('g', "call-graph", &call_graph,
		    "do call-graph (stack chain/backtrace) recording"),
	OPT_INCR('v', "verbose", &verbose,
		    "be more verbose (show counter open errors, etc)"),
	OPT_BOOLEAN('s', "stat", &inherit_stat,
		    "per thread counts"),
	OPT_BOOLEAN('d', "data", &sample_address,
		    "Sample addresses"),
	OPT_BOOLEAN('n', "no-samples", &no_samples,
		    "don't sample"),
	OPT_BOOLEAN('M', "multiplex", &multiplex,
		    "multiplex counter output in a single channel"),
	OPT_END()
};

int cmd_record(int argc, const char **argv, const char *prefix __used)
{
	int i,j;

	argc = parse_options(argc, argv, options, record_usage,
			    PARSE_OPT_STOP_AT_NON_OPTION);
	if (!argc && target_pid == -1 && target_tid == -1 &&
		!system_wide && profile_cpu == -1)
		usage_with_options(record_usage, options);

	if (force && append_file) {
		fprintf(stderr, "Can't overwrite and append at the same time."
				" You need to choose between -f and -A");
		usage_with_options(record_usage, options);
	} else if (append_file) {
		write_mode = WRITE_APPEND;
	} else {
		write_mode = WRITE_FORCE;
	}

	symbol__init();

	if (!nr_counters) {
		nr_counters	= 1;
		attrs[0].type	= PERF_TYPE_HARDWARE;
		attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
	}

	if (target_pid != -1) {
		target_tid = target_pid;
		thread_num = find_all_tid(target_pid, &all_tids);
		if (thread_num <= 0) {
			fprintf(stderr, "Can't find all threads of pid %d\n",
					target_pid);
			usage_with_options(record_usage, options);
		}
	} else {
		all_tids=malloc(sizeof(pid_t));
		if (!all_tids)
			return -ENOMEM;

		all_tids[0] = target_tid;
		thread_num = 1;
	}

	for (i = 0; i < MAX_NR_CPUS; i++) {
		for (j = 0; j < MAX_COUNTERS; j++) {
			fd[i][j] = malloc(sizeof(int)*thread_num);
			mmap_array[i][j] = zalloc(
				sizeof(struct mmap_data)*thread_num);
			if (!fd[i][j] || !mmap_array[i][j])
				return -ENOMEM;
		}
	}
	event_array = malloc(
		sizeof(struct pollfd)*MAX_NR_CPUS*MAX_COUNTERS*thread_num);
	if (!event_array)
		return -ENOMEM;

	if (user_interval != UINT_MAX)
		default_interval = user_interval;
	if (user_freq != UINT_MAX)
		freq = user_freq;

	/*
	 * User specified count overrides default frequency.
	 */
	if (default_interval)
		freq = 0;
	else if (freq) {
		default_interval = freq;
	} else {
		fprintf(stderr, "frequency and count are zero, aborting\n");
		exit(EXIT_FAILURE);
	}

	return __cmd_record(argc, argv);
}