aboutsummaryrefslogtreecommitdiff
path: root/tools/perf/builtin-top.c
blob: c051833f755cc4657a6dd44b945b2f94621ea6cb (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
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
/*
 * builtin-top.c
 *
 * Builtin top command: Display a continuously updated profile of
 * any workload, CPU or specific PID.
 *
 * 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>
 *
 * Released under the GPL v2. (and only v2, not any later version)
 */
#include "builtin.h"

#include "perf.h"

#include "util/color.h"
#include "util/session.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/util.h"
#include <linux/rbtree.h>
#include "util/parse-options.h"
#include "util/parse-events.h"

#include "util/debug.h"

#include <assert.h>
#include <fcntl.h>

#include <stdio.h>
#include <termios.h>
#include <unistd.h>

#include <errno.h>
#include <time.h>
#include <sched.h>
#include <pthread.h>

#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <sys/poll.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <sys/uio.h>
#include <sys/mman.h>

#include <linux/unistd.h>
#include <linux/types.h>

static int			fd[MAX_NR_CPUS][MAX_COUNTERS];

static int			system_wide			=      0;

static int			default_interval		=      0;

static int			count_filter			=      5;
static int			print_entries;

static int			target_pid			=     -1;
static int			inherit				=      0;
static int			profile_cpu			=     -1;
static int			nr_cpus				=      0;
static unsigned int		realtime_prio			=      0;
static int			group				=      0;
static unsigned int		page_size;
static unsigned int		mmap_pages			=     16;
static int			freq				=   1000; /* 1 KHz */

static int			delay_secs			=      2;
static int			zero                            =      0;
static int			dump_symtab                     =      0;

static bool			hide_kernel_symbols		=  false;
static bool			hide_user_symbols		=  false;
static struct winsize		winsize;

/*
 * Source
 */

struct source_line {
	u64			eip;
	unsigned long		count[MAX_COUNTERS];
	char			*line;
	struct source_line	*next;
};

static char			*sym_filter			=   NULL;
struct sym_entry		*sym_filter_entry		=   NULL;
struct sym_entry		*sym_filter_entry_sched		=   NULL;
static int			sym_pcnt_filter			=      5;
static int			sym_counter			=      0;
static int			display_weighted		=     -1;

/*
 * Symbols
 */

struct sym_entry_source {
	struct source_line	*source;
	struct source_line	*lines;
	struct source_line	**lines_tail;
	pthread_mutex_t		lock;
};

struct sym_entry {
	struct rb_node		rb_node;
	struct list_head	node;
	unsigned long		snap_count;
	double			weight;
	int			skip;
	u16			name_len;
	u8			origin;
	struct map		*map;
	struct sym_entry_source	*src;
	unsigned long		count[0];
};

/*
 * Source functions
 */

static inline struct symbol *sym_entry__symbol(struct sym_entry *self)
{
       return ((void *)self) + symbol_conf.priv_size;
}

static void get_term_dimensions(struct winsize *ws)
{
	char *s = getenv("LINES");

	if (s != NULL) {
		ws->ws_row = atoi(s);
		s = getenv("COLUMNS");
		if (s != NULL) {
			ws->ws_col = atoi(s);
			if (ws->ws_row && ws->ws_col)
				return;
		}
	}
#ifdef TIOCGWINSZ
	if (ioctl(1, TIOCGWINSZ, ws) == 0 &&
	    ws->ws_row && ws->ws_col)
		return;
#endif
	ws->ws_row = 25;
	ws->ws_col = 80;
}

static void update_print_entries(struct winsize *ws)
{
	print_entries = ws->ws_row;

	if (print_entries > 9)
		print_entries -= 9;
}

static void sig_winch_handler(int sig __used)
{
	get_term_dimensions(&winsize);
	update_print_entries(&winsize);
}

static void parse_source(struct sym_entry *syme)
{
	struct symbol *sym;
	struct sym_entry_source *source;
	struct map *map;
	FILE *file;
	char command[PATH_MAX*2];
	const char *path;
	u64 len;

	if (!syme)
		return;

	if (syme->src == NULL) {
		syme->src = zalloc(sizeof(*source));
		if (syme->src == NULL)
			return;
		pthread_mutex_init(&syme->src->lock, NULL);
	}

	source = syme->src;

	if (source->lines) {
		pthread_mutex_lock(&source->lock);
		goto out_assign;
	}

	sym = sym_entry__symbol(syme);
	map = syme->map;
	path = map->dso->long_name;

	len = sym->end - sym->start;

	sprintf(command,
		"objdump --start-address=%#0*Lx --stop-address=%#0*Lx -dS %s",
		BITS_PER_LONG / 4, map__rip_2objdump(map, sym->start),
		BITS_PER_LONG / 4, map__rip_2objdump(map, sym->end), path);

	file = popen(command, "r");
	if (!file)
		return;

	pthread_mutex_lock(&source->lock);
	source->lines_tail = &source->lines;
	while (!feof(file)) {
		struct source_line *src;
		size_t dummy = 0;
		char *c, *sep;

		src = malloc(sizeof(struct source_line));
		assert(src != NULL);
		memset(src, 0, sizeof(struct source_line));

		if (getline(&src->line, &dummy, file) < 0)
			break;
		if (!src->line)
			break;

		c = strchr(src->line, '\n');
		if (c)
			*c = 0;

		src->next = NULL;
		*source->lines_tail = src;
		source->lines_tail = &src->next;

		src->eip = strtoull(src->line, &sep, 16);
		if (*sep == ':')
			src->eip = map__objdump_2ip(map, src->eip);
		else /* this line has no ip info (e.g. source line) */
			src->eip = 0;
	}
	pclose(file);
out_assign:
	sym_filter_entry = syme;
	pthread_mutex_unlock(&source->lock);
}

static void __zero_source_counters(struct sym_entry *syme)
{
	int i;
	struct source_line *line;

	line = syme->src->lines;
	while (line) {
		for (i = 0; i < nr_counters; i++)
			line->count[i] = 0;
		line = line->next;
	}
}

static void record_precise_ip(struct sym_entry *syme, int counter, u64 ip)
{
	struct source_line *line;

	if (syme != sym_filter_entry)
		return;

	if (pthread_mutex_trylock(&syme->src->lock))
		return;

	if (syme->src == NULL || syme->src->source == NULL)
		goto out_unlock;

	for (line = syme->src->lines; line; line = line->next) {
		/* skip lines without IP info */
		if (line->eip == 0)
			continue;
		if (line->eip == ip) {
			line->count[counter]++;
			break;
		}
		if (line->eip > ip)
			break;
	}
out_unlock:
	pthread_mutex_unlock(&syme->src->lock);
}

#define PATTERN_LEN		(BITS_PER_LONG / 4 + 2)

static void lookup_sym_source(struct sym_entry *syme)
{
	struct symbol *symbol = sym_entry__symbol(syme);
	struct source_line *line;
	char pattern[PATTERN_LEN + 1];

	sprintf(pattern, "%0*Lx <", BITS_PER_LONG / 4,
		map__rip_2objdump(syme->map, symbol->start));

	pthread_mutex_lock(&syme->src->lock);
	for (line = syme->src->lines; line; line = line->next) {
		if (memcmp(line->line, pattern, PATTERN_LEN) == 0) {
			syme->src->source = line;
			break;
		}
	}
	pthread_mutex_unlock(&syme->src->lock);
}

static void show_lines(struct source_line *queue, int count, int total)
{
	int i;
	struct source_line *line;

	line = queue;
	for (i = 0; i < count; i++) {
		float pcnt = 100.0*(float)line->count[sym_counter]/(float)total;

		printf("%8li %4.1f%%\t%s\n", line->count[sym_counter], pcnt, line->line);
		line = line->next;
	}
}

#define TRACE_COUNT     3

static void show_details(struct sym_entry *syme)
{
	struct symbol *symbol;
	struct source_line *line;
	struct source_line *line_queue = NULL;
	int displayed = 0;
	int line_queue_count = 0, total = 0, more = 0;

	if (!syme)
		return;

	if (!syme->src->source)
		lookup_sym_source(syme);

	if (!syme->src->source)
		return;

	symbol = sym_entry__symbol(syme);
	printf("Showing %s for %s\n", event_name(sym_counter), symbol->name);
	printf("  Events  Pcnt (>=%d%%)\n", sym_pcnt_filter);

	pthread_mutex_lock(&syme->src->lock);
	line = syme->src->source;
	while (line) {
		total += line->count[sym_counter];
		line = line->next;
	}

	line = syme->src->source;
	while (line) {
		float pcnt = 0.0;

		if (!line_queue_count)
			line_queue = line;
		line_queue_count++;

		if (line->count[sym_counter])
			pcnt = 100.0 * line->count[sym_counter] / (float)total;
		if (pcnt >= (float)sym_pcnt_filter) {
			if (displayed <= print_entries)
				show_lines(line_queue, line_queue_count, total);
			else more++;
			displayed += line_queue_count;
			line_queue_count = 0;
			line_queue = NULL;
		} else if (line_queue_count > TRACE_COUNT) {
			line_queue = line_queue->next;
			line_queue_count--;
		}

		line->count[sym_counter] = zero ? 0 : line->count[sym_counter] * 7 / 8;
		line = line->next;
	}
	pthread_mutex_unlock(&syme->src->lock);
	if (more)
		printf("%d lines not displayed, maybe increase display entries [e]\n", more);
}

/*
 * Symbols will be added here in event__process_sample and will get out
 * after decayed.
 */
static LIST_HEAD(active_symbols);
static pthread_mutex_t active_symbols_lock = PTHREAD_MUTEX_INITIALIZER;

/*
 * Ordering weight: count-1 * count-2 * ... / count-n
 */
static double sym_weight(const struct sym_entry *sym)
{
	double weight = sym->snap_count;
	int counter;

	if (!display_weighted)
		return weight;

	for (counter = 1; counter < nr_counters-1; counter++)
		weight *= sym->count[counter];

	weight /= (sym->count[counter] + 1);

	return weight;
}

static long			samples;
static long			userspace_samples;
static long			exact_samples;
static const char		CONSOLE_CLEAR[] = "";

static void __list_insert_active_sym(struct sym_entry *syme)
{
	list_add(&syme->node, &active_symbols);
}

static void list_remove_active_sym(struct sym_entry *syme)
{
	pthread_mutex_lock(&active_symbols_lock);
	list_del_init(&syme->node);
	pthread_mutex_unlock(&active_symbols_lock);
}

static void rb_insert_active_sym(struct rb_root *tree, struct sym_entry *se)
{
	struct rb_node **p = &tree->rb_node;
	struct rb_node *parent = NULL;
	struct sym_entry *iter;

	while (*p != NULL) {
		parent = *p;
		iter = rb_entry(parent, struct sym_entry, rb_node);

		if (se->weight > iter->weight)
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}

	rb_link_node(&se->rb_node, parent, p);
	rb_insert_color(&se->rb_node, tree);
}

static void print_sym_table(void)
{
	int printed = 0, j;
	int counter, snap = !display_weighted ? sym_counter : 0;
	float samples_per_sec = samples/delay_secs;
	float ksamples_per_sec = (samples-userspace_samples)/delay_secs;
	float esamples_percent = (100.0*exact_samples)/samples;
	float sum_ksamples = 0.0;
	struct sym_entry *syme, *n;
	struct rb_root tmp = RB_ROOT;
	struct rb_node *nd;
	int sym_width = 0, dso_width = 0, max_dso_width;
	const int win_width = winsize.ws_col - 1;

	samples = userspace_samples = exact_samples = 0;

	/* Sort the active symbols */
	pthread_mutex_lock(&active_symbols_lock);
	syme = list_entry(active_symbols.next, struct sym_entry, node);
	pthread_mutex_unlock(&active_symbols_lock);

	list_for_each_entry_safe_from(syme, n, &active_symbols, node) {
		syme->snap_count = syme->count[snap];
		if (syme->snap_count != 0) {

			if ((hide_user_symbols &&
			     syme->origin == PERF_RECORD_MISC_USER) ||
			    (hide_kernel_symbols &&
			     syme->origin == PERF_RECORD_MISC_KERNEL)) {
				list_remove_active_sym(syme);
				continue;
			}
			syme->weight = sym_weight(syme);
			rb_insert_active_sym(&tmp, syme);
			sum_ksamples += syme->snap_count;

			for (j = 0; j < nr_counters; j++)
				syme->count[j] = zero ? 0 : syme->count[j] * 7 / 8;
		} else
			list_remove_active_sym(syme);
	}

	puts(CONSOLE_CLEAR);

	printf("%-*.*s\n", win_width, win_width, graph_dotted_line);
	printf( "   PerfTop:%8.0f irqs/sec  kernel:%4.1f%%  exact: %4.1f%% [",
		samples_per_sec,
		100.0 - (100.0*((samples_per_sec-ksamples_per_sec)/samples_per_sec)),
		esamples_percent);

	if (nr_counters == 1 || !display_weighted) {
		printf("%Ld", (u64)attrs[0].sample_period);
		if (freq)
			printf("Hz ");
		else
			printf(" ");
	}

	if (!display_weighted)
		printf("%s", event_name(sym_counter));
	else for (counter = 0; counter < nr_counters; counter++) {
		if (counter)
			printf("/");

		printf("%s", event_name(counter));
	}

	printf( "], ");

	if (target_pid != -1)
		printf(" (target_pid: %d", target_pid);
	else
		printf(" (all");

	if (profile_cpu != -1)
		printf(", cpu: %d)\n", profile_cpu);
	else {
		if (target_pid != -1)
			printf(")\n");
		else
			printf(", %d CPUs)\n", nr_cpus);
	}

	printf("%-*.*s\n", win_width, win_width, graph_dotted_line);

	if (sym_filter_entry) {
		show_details(sym_filter_entry);
		return;
	}

	/*
	 * Find the longest symbol name that will be displayed
	 */
	for (nd = rb_first(&tmp); nd; nd = rb_next(nd)) {
		syme = rb_entry(nd, struct sym_entry, rb_node);
		if (++printed > print_entries ||
		    (int)syme->snap_count < count_filter)
			continue;

		if (syme->map->dso->long_name_len > dso_width)
			dso_width = syme->map->dso->long_name_len;

		if (syme->name_len > sym_width)
			sym_width = syme->name_len;
	}

	printed = 0;

	max_dso_width = winsize.ws_col - sym_width - 29;
	if (dso_width > max_dso_width)
		dso_width = max_dso_width;
	putchar('\n');
	if (nr_counters == 1)
		printf("             samples  pcnt");
	else
		printf("   weight    samples  pcnt");

	if (verbose)
		printf("         RIP       ");
	printf(" %-*.*s DSO\n", sym_width, sym_width, "function");
	printf("   %s    _______ _____",
	       nr_counters == 1 ? "      " : "______");
	if (verbose)
		printf(" ________________");
	printf(" %-*.*s", sym_width, sym_width, graph_line);
	printf(" %-*.*s", dso_width, dso_width, graph_line);
	puts("\n");

	for (nd = rb_first(&tmp); nd; nd = rb_next(nd)) {
		struct symbol *sym;
		double pcnt;

		syme = rb_entry(nd, struct sym_entry, rb_node);
		sym = sym_entry__symbol(syme);

		if (++printed > print_entries || (int)syme->snap_count < count_filter)
			continue;

		pcnt = 100.0 - (100.0 * ((sum_ksamples - syme->snap_count) /
					 sum_ksamples));

		if (nr_counters == 1 || !display_weighted)
			printf("%20.2f ", syme->weight);
		else
			printf("%9.1f %10ld ", syme->weight, syme->snap_count);

		percent_color_fprintf(stdout, "%4.1f%%", pcnt);
		if (verbose)
			printf(" %016llx", sym->start);
		printf(" %-*.*s", sym_width, sym_width, sym->name);
		printf(" %-*.*s\n", dso_width, dso_width,
		       dso_width >= syme->map->dso->long_name_len ?
					syme->map->dso->long_name :
					syme->map->dso->short_name);
	}
}

static void prompt_integer(int *target, const char *msg)
{
	char *buf = malloc(0), *p;
	size_t dummy = 0;
	int tmp;

	fprintf(stdout, "\n%s: ", msg);
	if (getline(&buf, &dummy, stdin) < 0)
		return;

	p = strchr(buf, '\n');
	if (p)
		*p = 0;

	p = buf;
	while(*p) {
		if (!isdigit(*p))
			goto out_free;
		p++;
	}
	tmp = strtoul(buf, NULL, 10);
	*target = tmp;
out_free:
	free(buf);
}

static void prompt_percent(int *target, const char *msg)
{
	int tmp = 0;

	prompt_integer(&tmp, msg);
	if (tmp >= 0 && tmp <= 100)
		*target = tmp;
}

static void prompt_symbol(struct sym_entry **target, const char *msg)
{
	char *buf = malloc(0), *p;
	struct sym_entry *syme = *target, *n, *found = NULL;
	size_t dummy = 0;

	/* zero counters of active symbol */
	if (syme) {
		pthread_mutex_lock(&syme->src->lock);
		__zero_source_counters(syme);
		*target = NULL;
		pthread_mutex_unlock(&syme->src->lock);
	}

	fprintf(stdout, "\n%s: ", msg);
	if (getline(&buf, &dummy, stdin) < 0)
		goto out_free;

	p = strchr(buf, '\n');
	if (p)
		*p = 0;

	pthread_mutex_lock(&active_symbols_lock);
	syme = list_entry(active_symbols.next, struct sym_entry, node);
	pthread_mutex_unlock(&active_symbols_lock);

	list_for_each_entry_safe_from(syme, n, &active_symbols, node) {
		struct symbol *sym = sym_entry__symbol(syme);

		if (!strcmp(buf, sym->name)) {
			found = syme;
			break;
		}
	}

	if (!found) {
		fprintf(stderr, "Sorry, %s is not active.\n", buf);
		sleep(1);
		return;
	} else
		parse_source(found);

out_free:
	free(buf);
}

static void print_mapped_keys(void)
{
	char *name = NULL;

	if (sym_filter_entry) {
		struct symbol *sym = sym_entry__symbol(sym_filter_entry);
		name = sym->name;
	}

	fprintf(stdout, "\nMapped keys:\n");
	fprintf(stdout, "\t[d]     display refresh delay.             \t(%d)\n", delay_secs);
	fprintf(stdout, "\t[e]     display entries (lines).           \t(%d)\n", print_entries);

	if (nr_counters > 1)
		fprintf(stdout, "\t[E]     active event counter.              \t(%s)\n", event_name(sym_counter));

	fprintf(stdout, "\t[f]     profile display filter (count).    \t(%d)\n", count_filter);

	fprintf(stdout, "\t[F]     annotate display filter (percent). \t(%d%%)\n", sym_pcnt_filter);
	fprintf(stdout, "\t[s]     annotate symbol.                   \t(%s)\n", name?: "NULL");
	fprintf(stdout, "\t[S]     stop annotation.\n");

	if (nr_counters > 1)
		fprintf(stdout, "\t[w]     toggle display weighted/count[E]r. \t(%d)\n", display_weighted ? 1 : 0);

	fprintf(stdout,
		"\t[K]     hide kernel_symbols symbols.     \t(%s)\n",
		hide_kernel_symbols ? "yes" : "no");
	fprintf(stdout,
		"\t[U]     hide user symbols.               \t(%s)\n",
		hide_user_symbols ? "yes" : "no");
	fprintf(stdout, "\t[z]     toggle sample zeroing.             \t(%d)\n", zero ? 1 : 0);
	fprintf(stdout, "\t[qQ]    quit.\n");
}

static int key_mapped(int c)
{
	switch (c) {
		case 'd':
		case 'e':
		case 'f':
		case 'z':
		case 'q':
		case 'Q':
		case 'K':
		case 'U':
		case 'F':
		case 's':
		case 'S':
			return 1;
		case 'E':
		case 'w':
			return nr_counters > 1 ? 1 : 0;
		default:
			break;
	}

	return 0;
}

static void handle_keypress(int c)
{
	if (!key_mapped(c)) {
		struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
		struct termios tc, save;

		print_mapped_keys();
		fprintf(stdout, "\nEnter selection, or unmapped key to continue: ");
		fflush(stdout);

		tcgetattr(0, &save);
		tc = save;
		tc.c_lflag &= ~(ICANON | ECHO);
		tc.c_cc[VMIN] = 0;
		tc.c_cc[VTIME] = 0;
		tcsetattr(0, TCSANOW, &tc);

		poll(&stdin_poll, 1, -1);
		c = getc(stdin);

		tcsetattr(0, TCSAFLUSH, &save);
		if (!key_mapped(c))
			return;
	}

	switch (c) {
		case 'd':
			prompt_integer(&delay_secs, "Enter display delay");
			if (delay_secs < 1)
				delay_secs = 1;
			break;
		case 'e':
			prompt_integer(&print_entries, "Enter display entries (lines)");
			if (print_entries == 0) {
				sig_winch_handler(SIGWINCH);
				signal(SIGWINCH, sig_winch_handler);
			} else
				signal(SIGWINCH, SIG_DFL);
			break;
		case 'E':
			if (nr_counters > 1) {
				int i;

				fprintf(stderr, "\nAvailable events:");
				for (i = 0; i < nr_counters; i++)
					fprintf(stderr, "\n\t%d %s", i, event_name(i));

				prompt_integer(&sym_counter, "Enter details event counter");

				if (sym_counter >= nr_counters) {
					fprintf(stderr, "Sorry, no such event, using %s.\n", event_name(0));
					sym_counter = 0;
					sleep(1);
				}
			} else sym_counter = 0;
			break;
		case 'f':
			prompt_integer(&count_filter, "Enter display event count filter");
			break;
		case 'F':
			prompt_percent(&sym_pcnt_filter, "Enter details display event filter (percent)");
			break;
		case 'K':
			hide_kernel_symbols = !hide_kernel_symbols;
			break;
		case 'q':
		case 'Q':
			printf("exiting.\n");
			if (dump_symtab)
				dsos__fprintf(stderr);
			exit(0);
		case 's':
			prompt_symbol(&sym_filter_entry, "Enter details symbol");
			break;
		case 'S':
			if (!sym_filter_entry)
				break;
			else {
				struct sym_entry *syme = sym_filter_entry;

				pthread_mutex_lock(&syme->src->lock);
				sym_filter_entry = NULL;
				__zero_source_counters(syme);
				pthread_mutex_unlock(&syme->src->lock);
			}
			break;
		case 'U':
			hide_user_symbols = !hide_user_symbols;
			break;
		case 'w':
			display_weighted = ~display_weighted;
			break;
		case 'z':
			zero = ~zero;
			break;
		default:
			break;
	}
}

static void *display_thread(void *arg __used)
{
	struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
	struct termios tc, save;
	int delay_msecs, c;

	tcgetattr(0, &save);
	tc = save;
	tc.c_lflag &= ~(ICANON | ECHO);
	tc.c_cc[VMIN] = 0;
	tc.c_cc[VTIME] = 0;

repeat:
	delay_msecs = delay_secs * 1000;
	tcsetattr(0, TCSANOW, &tc);
	/* trash return*/
	getc(stdin);

	do {
		print_sym_table();
	} while (!poll(&stdin_poll, 1, delay_msecs) == 1);

	c = getc(stdin);
	tcsetattr(0, TCSAFLUSH, &save);

	handle_keypress(c);
	goto repeat;

	return NULL;
}

/* Tag samples to be skipped. */
static const char *skip_symbols[] = {
	"default_idle",
	"cpu_idle",
	"enter_idle",
	"exit_idle",
	"mwait_idle",
	"mwait_idle_with_hints",
	"poll_idle",
	"ppc64_runlatch_off",
	"pseries_dedicated_idle_sleep",
	NULL
};

static int symbol_filter(struct map *map, struct symbol *sym)
{
	struct sym_entry *syme;
	const char *name = sym->name;
	int i;

	/*
	 * ppc64 uses function descriptors and appends a '.' to the
	 * start of every instruction address. Remove it.
	 */
	if (name[0] == '.')
		name++;

	if (!strcmp(name, "_text") ||
	    !strcmp(name, "_etext") ||
	    !strcmp(name, "_sinittext") ||
	    !strncmp("init_module", name, 11) ||
	    !strncmp("cleanup_module", name, 14) ||
	    strstr(name, "_text_start") ||
	    strstr(name, "_text_end"))
		return 1;

	syme = symbol__priv(sym);
	syme->map = map;
	syme->src = NULL;

	if (!sym_filter_entry && sym_filter && !strcmp(name, sym_filter)) {
		/* schedule initial sym_filter_entry setup */
		sym_filter_entry_sched = syme;
		sym_filter = NULL;
	}

	for (i = 0; skip_symbols[i]; i++) {
		if (!strcmp(skip_symbols[i], name)) {
			syme->skip = 1;
			break;
		}
	}

	if (!syme->skip)
		syme->name_len = strlen(sym->name);

	return 0;
}

static void event__process_sample(const event_t *self,
				 struct perf_session *session, int counter)
{
	u64 ip = self->ip.ip;
	struct sym_entry *syme;
	struct addr_location al;
	u8 origin = self->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;

	++samples;

	switch (origin) {
	case PERF_RECORD_MISC_USER:
		++userspace_samples;
		if (hide_user_symbols)
			return;
		break;
	case PERF_RECORD_MISC_KERNEL:
		if (hide_kernel_symbols)
			return;
		break;
	default:
		return;
	}

	if (self->header.misc & PERF_RECORD_MISC_EXACT)
		exact_samples++;

	if (event__preprocess_sample(self, session, &al, symbol_filter) < 0 ||
	    al.filtered)
		return;

	if (al.sym == NULL) {
		/*
		 * As we do lazy loading of symtabs we only will know if the
		 * specified vmlinux file is invalid when we actually have a
		 * hit in kernel space and then try to load it. So if we get
		 * here and there are _no_ symbols in the DSO backing the
		 * kernel map, bail out.
		 *
		 * We may never get here, for instance, if we use -K/
		 * --hide-kernel-symbols, even if the user specifies an
		 * invalid --vmlinux ;-)
		 */
		if (al.map == session->vmlinux_maps[MAP__FUNCTION] &&
		    RB_EMPTY_ROOT(&al.map->dso->symbols[MAP__FUNCTION])) {
			pr_err("The %s file can't be used\n",
			       symbol_conf.vmlinux_name);
			exit(1);
		}

		return;
	}

	/* let's see, whether we need to install initial sym_filter_entry */
	if (sym_filter_entry_sched) {
		sym_filter_entry = sym_filter_entry_sched;
		sym_filter_entry_sched = NULL;
		parse_source(sym_filter_entry);
	}

	syme = symbol__priv(al.sym);
	if (!syme->skip) {
		syme->count[counter]++;
		syme->origin = origin;
		record_precise_ip(syme, counter, ip);
		pthread_mutex_lock(&active_symbols_lock);
		if (list_empty(&syme->node) || !syme->node.next)
			__list_insert_active_sym(syme);
		pthread_mutex_unlock(&active_symbols_lock);
	}
}

static int event__process(event_t *event, struct perf_session *session)
{
	switch (event->header.type) {
	case PERF_RECORD_COMM:
		event__process_comm(event, session);
		break;
	case PERF_RECORD_MMAP:
		event__process_mmap(event, session);
		break;
	case PERF_RECORD_FORK:
	case PERF_RECORD_EXIT:
		event__process_task(event, session);
		break;
	default:
		break;
	}

	return 0;
}

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

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

	head = pc->data_head;
	rmb();

	return head;
}

static void perf_session__mmap_read_counter(struct perf_session *self,
					    struct mmap_data *md)
{
	unsigned int head = mmap_read_head(md);
	unsigned int old = md->prev;
	unsigned char *data = md->base + page_size;
	int diff;

	/*
	 * 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 > md->mask / 2 || diff < 0) {
		fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");

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

	for (; old != head;) {
		event_t *event = (event_t *)&data[old & md->mask];

		event_t event_copy;

		size_t size = event->header.size;

		/*
		 * Event straddles the mmap boundary -- header should always
		 * be inside due to u64 alignment of output.
		 */
		if ((old & md->mask) + size != ((old + size) & md->mask)) {
			unsigned int offset = old;
			unsigned int len = min(sizeof(*event), size), cpy;
			void *dst = &event_copy;

			do {
				cpy = min(md->mask + 1 - (offset & md->mask), len);
				memcpy(dst, &data[offset & md->mask], cpy);
				offset += cpy;
				dst += cpy;
				len -= cpy;
			} while (len);

			event = &event_copy;
		}

		if (event->header.type == PERF_RECORD_SAMPLE)
			event__process_sample(event, self, md->counter);
		else
			event__process(event, self);
		old += size;
	}

	md->prev = old;
}

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

static void perf_session__mmap_read(struct perf_session *self)
{
	int i, counter;

	for (i = 0; i < nr_cpus; i++) {
		for (counter = 0; counter < nr_counters; counter++)
			perf_session__mmap_read_counter(self, &mmap_array[i][counter]);
	}
}

int nr_poll;
int group_fd;

static void start_counter(int i, int counter)
{
	struct perf_event_attr *attr;
	int cpu;

	cpu = profile_cpu;
	if (target_pid == -1 && profile_cpu == -1)
		cpu = i;

	attr = attrs + counter;

	attr->sample_type	= PERF_SAMPLE_IP | PERF_SAMPLE_TID;

	if (freq) {
		attr->sample_type	|= PERF_SAMPLE_PERIOD;
		attr->freq		= 1;
		attr->sample_freq	= freq;
	}

	attr->inherit		= (cpu < 0) && inherit;
	attr->mmap		= 1;

try_again:
	fd[i][counter] = sys_perf_event_open(attr, target_pid, cpu, group_fd, 0);

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

		if (err == EPERM || err == EACCES)
			die("No permission - are you root?\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[i][counter], strerror(err));
		die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
		exit(-1);
	}
	assert(fd[i][counter] >= 0);
	fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);

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

	event_array[nr_poll].fd = fd[i][counter];
	event_array[nr_poll].events = POLLIN;
	nr_poll++;

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

static int __cmd_top(void)
{
	pthread_t thread;
	int i, counter;
	int ret;
	/*
	 * FIXME: perf_session__new should allow passing a O_MMAP, so that all this
	 * mmap reading, etc is encapsulated in it. Use O_WRONLY for now.
	 */
	struct perf_session *session = perf_session__new(NULL, O_WRONLY, false);
	if (session == NULL)
		return -ENOMEM;

	if (target_pid != -1)
		event__synthesize_thread(target_pid, event__process, session);
	else
		event__synthesize_threads(event__process, session);

	for (i = 0; i < nr_cpus; i++) {
		group_fd = -1;
		for (counter = 0; counter < nr_counters; counter++)
			start_counter(i, counter);
	}

	/* Wait for a minimal set of events before starting the snapshot */
	poll(event_array, nr_poll, 100);

	perf_session__mmap_read(session);

	if (pthread_create(&thread, NULL, display_thread, NULL)) {
		printf("Could not create display thread.\n");
		exit(-1);
	}

	if (realtime_prio) {
		struct sched_param param;

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

	while (1) {
		int hits = samples;

		perf_session__mmap_read(session);

		if (hits == samples)
			ret = poll(event_array, nr_poll, 100);
	}

	return 0;
}

static const char * const top_usage[] = {
	"perf top [<options>]",
	NULL
};

static const struct option options[] = {
	OPT_CALLBACK('e', "event", NULL, "event",
		     "event selector. use 'perf list' to list available events",
		     parse_events),
	OPT_INTEGER('c', "count", &default_interval,
		    "event period to sample"),
	OPT_INTEGER('p', "pid", &target_pid,
		    "profile events on existing pid"),
	OPT_BOOLEAN('a', "all-cpus", &system_wide,
			    "system-wide collection from all CPUs"),
	OPT_INTEGER('C', "CPU", &profile_cpu,
		    "CPU to profile on"),
	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
		   "file", "vmlinux pathname"),
	OPT_BOOLEAN('K', "hide_kernel_symbols", &hide_kernel_symbols,
		    "hide kernel symbols"),
	OPT_INTEGER('m', "mmap-pages", &mmap_pages,
		    "number of mmap data pages"),
	OPT_INTEGER('r', "realtime", &realtime_prio,
		    "collect data with this RT SCHED_FIFO priority"),
	OPT_INTEGER('d', "delay", &delay_secs,
		    "number of seconds to delay between refreshes"),
	OPT_BOOLEAN('D', "dump-symtab", &dump_symtab,
			    "dump the symbol table used for profiling"),
	OPT_INTEGER('f', "count-filter", &count_filter,
		    "only display functions with more events than this"),
	OPT_BOOLEAN('g', "group", &group,
			    "put the counters into a counter group"),
	OPT_BOOLEAN('i', "inherit", &inherit,
		    "child tasks inherit counters"),
	OPT_STRING('s', "sym-annotate", &sym_filter, "symbol name",
		    "symbol to annotate"),
	OPT_BOOLEAN('z', "zero", &zero,
		    "zero history across updates"),
	OPT_INTEGER('F', "freq", &freq,
		    "profile at this frequency"),
	OPT_INTEGER('E', "entries", &print_entries,
		    "display this many functions"),
	OPT_BOOLEAN('U', "hide_user_symbols", &hide_user_symbols,
		    "hide user symbols"),
	OPT_BOOLEAN('v', "verbose", &verbose,
		    "be more verbose (show counter open errors, etc)"),
	OPT_END()
};

int cmd_top(int argc, const char **argv, const char *prefix __used)
{
	int counter;

	page_size = sysconf(_SC_PAGE_SIZE);

	argc = parse_options(argc, argv, options, top_usage, 0);
	if (argc)
		usage_with_options(top_usage, options);

	/* CPU and PID are mutually exclusive */
	if (target_pid != -1 && profile_cpu != -1) {
		printf("WARNING: PID switch overriding CPU\n");
		sleep(1);
		profile_cpu = -1;
	}

	if (!nr_counters)
		nr_counters = 1;

	symbol_conf.priv_size = (sizeof(struct sym_entry) +
				 (nr_counters + 1) * sizeof(unsigned long));

	symbol_conf.try_vmlinux_path = (symbol_conf.vmlinux_name == NULL);
	if (symbol__init() < 0)
		return -1;

	if (delay_secs < 1)
		delay_secs = 1;

	/*
	 * 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);
	}

	/*
	 * Fill in the ones not specifically initialized via -c:
	 */
	for (counter = 0; counter < nr_counters; counter++) {
		if (attrs[counter].sample_period)
			continue;

		attrs[counter].sample_period = default_interval;
	}

	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
	assert(nr_cpus <= MAX_NR_CPUS);
	assert(nr_cpus >= 0);

	if (target_pid != -1 || profile_cpu != -1)
		nr_cpus = 1;

	get_term_dimensions(&winsize);
	if (print_entries == 0) {
		update_print_entries(&winsize);
		signal(SIGWINCH, sig_winch_handler);
	}

	return __cmd_top();
}