forked from iovisor/bcc
-
Notifications
You must be signed in to change notification settings - Fork 0
/
profile_example.txt
752 lines (640 loc) · 29.4 KB
/
profile_example.txt
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
Demonstrations of profile, the Linux eBPF/bcc version.
This is a CPU profiler. It works by taking samples of stack traces at timed
intervals, and frequency counting them in kernel context for efficiency.
Example output:
# ./profile
Sampling at 49 Hertz of all threads by user + kernel stack... Hit Ctrl-C to end.
^C
filemap_map_pages
handle_mm_fault
__do_page_fault
do_page_fault
page_fault
[unknown]
- cp (9036)
1
[unknown]
[unknown]
- sign-file (8877)
1
__clear_user
iov_iter_zero
read_iter_zero
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
read
- dd (25036)
4
func_a
main
__libc_start_main
[unknown]
- func_ab (13549)
5
The output was long; I truncated some lines ("[...]").
This default output prints stack traces, followed by a line to describe the
process (a dash, the process name, and a PID in parenthesis), and then an
integer count of how many times this stack trace was sampled.
The func_ab process is running the func_a() function, called by main(),
called by __libc_start_main(), and called by "[unknown]" with what looks
like a bogus address (1st column). That's evidence of a broken stack trace.
It's common for user-level software that hasn't been compiled with frame
pointers (in this case, libc).
The dd process has called read(), and then enters the kernel via
entry_SYSCALL_64_fastpath(), calling sys_read(), and so on. Yes, I'm now
reading it bottom up. That way follows the code flow.
By default, CPU idle stacks are excluded. They can be included with -I:
# ./profile -I
[...]
native_safe_halt
default_idle
arch_cpu_idle
default_idle_call
cpu_startup_entry
rest_init
start_kernel
x86_64_start_reservations
x86_64_start_kernel
- swapper/0 (0)
72
native_safe_halt
default_idle
arch_cpu_idle
default_idle_call
cpu_startup_entry
start_secondary
- swapper/1 (0)
75
The output above shows the most frequent stack was from the "swapper/1"
process (PID 0), running the native_safe_halt() function, which was called
by default_idle(), which was called by arch_cpu_idle(), and so on. This is
the idle thread. Stacks can be read top-down, to follow ancestry: child,
parent, grandparent, etc.
The dd process profiled ealrier is actually "dd if=/dev/zero of=/dev/null":
it's a simple workload to analyze that just moves bytes from /dev/zero to
/dev/null. Profiling just that process:
# ./profile -p 25036
Sampling at 49 Hertz of PID 25036 by user + kernel stack... Hit Ctrl-C to end.
^C
[unknown]
[unknown]
- dd (25036)
1
__write
- dd (25036)
1
read
- dd (25036)
1
[...]
[unknown]
[unknown]
- dd (25036)
2
entry_SYSCALL_64_fastpath
__write
[unknown]
- dd (25036)
3
entry_SYSCALL_64_fastpath
read
- dd (25036)
3
__clear_user
iov_iter_zero
read_iter_zero
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
read
[unknown]
- dd (25036)
3
__clear_user
iov_iter_zero
read_iter_zero
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
read
- dd (25036)
7
Again, I've truncated some lines. Now we're just analyzing the dd process.
The filtering is performed in kernel context, for efficiency.
This output has some "[unknown]" frames that probably have valid addresses,
but we're lacking the symbol translation. This is a common for all profilers
on Linux, and is usually fixable. See the DEBUGGING section of the profile(8)
man page.
Lets add delimiters between the user and kernel stacks, using -d:
# ./profile -p 25036 -d
^C
__vfs_write
sys_write
entry_SYSCALL_64_fastpath
--
__write
- dd (25036)
1
--
[unknown]
[unknown]
- dd (25036)
1
iov_iter_init
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
--
read
- dd (25036)
1
[...]
__clear_user
iov_iter_zero
read_iter_zero
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
--
read
- dd (25036)
9
In this mode, the delimiters are "--".
Here's another example, a func_ab program that runs two functions, func_a() and
func_b(). Profiling it for 5 seconds:
# ./profile -p `pgrep -n func_ab` 5
Sampling at 49 Hertz of PID 2930 by user + kernel stack for 5 secs.
func_a
main
__libc_start_main
[unknown]
- func_ab (2930)
2
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
3
func_a
main
__libc_start_main
[unknown]
- func_ab (2930)
5
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
12
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
19
func_a
main
__libc_start_main
[unknown]
- func_ab (2930)
22
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
64
func_a
main
__libc_start_main
[unknown]
- func_ab (2930)
72
Note that the same stack (2nd column) seems to be repeated. Weren't we doing
frequency counting and only printing unique stacks? We are, but in terms of
the raw addresses, not the symbols. See the 1st column: those stacks are
all unique.
We can output in "folded format", which puts the stack trace on one line,
separating frames with semi-colons. Eg:
# ./profile -f -p `pgrep -n func_ab` 5
func_ab;[unknown];__libc_start_main;main;func_a 2
func_ab;[unknown];__libc_start_main;main;func_b 2
func_ab;[unknown];__libc_start_main;main;func_a 11
func_ab;[unknown];__libc_start_main;main;func_b 12
func_ab;[unknown];__libc_start_main;main;func_a 23
func_ab;[unknown];__libc_start_main;main;func_b 28
func_ab;[unknown];__libc_start_main;main;func_b 57
func_ab;[unknown];__libc_start_main;main;func_a 64
I find this pretty useful for writing to files and later grepping.
Folded format can also be used by flame graph stack visualizers, including
the original implementation:
https://github.com/brendangregg/FlameGraph
I'd include delimiters, -d. For example:
# ./profile -df -p `pgrep -n func_ab` 5 > out.profile
# git clone https://github.com/brendangregg/FlameGraph
# ./FlameGraph/flamegraph.pl < out.profile > out.svg
(Yes, I could pipe profile directly into flamegraph.pl, however, I like to
keep the raw folded profiles around: can be useful for regenerating flamegraphs
with different options, and, for differential flame graphs.)
Some flamegraph.pl palettes recognize kernel annotations, which can be added
with -a. It simply adds a "_[k]" at the end of kernel function names.
For example:
# ./profile -adf -p `pgrep -n dd` 10
dd;[unknown] 1
dd;[unknown];[unknown] 1
dd;[unknown];[unknown] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];__fsnotify_parent_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];__fsnotify_parent_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fdget_pos_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];apparmor_file_permission_[k] 1
dd;[unknown] 1
dd;[unknown];[unknown] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fget_light_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];__fsnotify_parent_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fget_light_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];read_iter_zero_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__fsnotify_parent_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fsnotify_parent_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];fsnotify_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fdget_pos_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fget_light_[k] 1
dd;[unknown] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];__fsnotify_parent_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 1
dd;[unknown];[unknown] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;read 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];security_file_permission_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];fsnotify_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];fsnotify_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];apparmor_file_permission_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];__fsnotify_parent_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];apparmor_file_permission_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];iov_iter_init_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];__fsnotify_parent_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];__vfs_write_[k];write_null_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];__clear_user_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];security_file_permission_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fget_light_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__vfs_read_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];__vfs_write_[k] 1
dd;[unknown] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fsnotify_parent_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;[unknown];__write;-;sys_write_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fsnotify_parent_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];common_file_perm_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;[unknown];[unknown] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fget_light_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];vfs_read_[k] 1
dd;__write 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];vfs_read_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fget_light_[k] 1
dd;[unknown];[unknown] 1
dd;[unknown] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;[unknown] 1
dd;[unknown] 1
dd;[unknown];[unknown] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;__write 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fget_light_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k] 1
dd;[unknown] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fget_light_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k] 1
dd;[unknown];[unknown] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fdget_pos_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];_cond_resched_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];iov_iter_init_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];__fsnotify_parent_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];rw_verify_area_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];apparmor_file_permission_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 1
dd;[unknown] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];fsnotify_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fdget_pos_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];__vfs_write_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];apparmor_file_permission_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fget_light_[k] 1
dd;[unknown] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];fsnotify_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];fsnotify_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 1
dd;__write;-;entry_SYSCALL_64_fastpath_[k];vfs_write_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 1
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k] 1
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];fsnotify_[k] 1
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];apparmor_file_permission_[k] 2
dd;read;-;entry_SYSCALL_64_fastpath_[k];__fdget_pos_[k] 2
dd;[unknown];[unknown] 2
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];__fdget_pos_[k] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k];common_file_perm_[k] 2
dd;[unknown];[unknown] 2
dd;[unknown];[unknown] 2
dd;[unknown];[unknown] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 2
dd;[unknown];[unknown] 2
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];__clear_user_[k] 2
dd;__write;-;entry_SYSCALL_64_fastpath_[k];__fdget_pos_[k] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 2
dd;[unknown];[unknown] 2
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fget_light_[k] 2
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];rw_verify_area_[k];security_file_permission_[k];fsnotify_[k] 2
dd;__write;-;sys_write_[k] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];fsnotify_[k] 2
dd;[unknown];[unknown] 2
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 2
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 2
dd;read;-;SyS_read_[k] 2
dd;[unknown] 2
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k] 2
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];__fget_light_[k] 2
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k] 2
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k];rw_verify_area_[k];security_file_permission_[k];apparmor_file_permission_[k] 2
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];__clear_user_[k] 2
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];rw_verify_area_[k] 2
dd;[unknown];[unknown] 3
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];rw_verify_area_[k] 3
dd;[unknown];[unknown] 3
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 3
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 3
dd;[unknown];[unknown] 3
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 3
dd;[unknown];[unknown] 3
dd;[unknown];[unknown] 3
dd;__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 3
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 3
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 3
dd;[unknown] 4
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 4
dd;[unknown];[unknown] 4
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k] 4
dd;[unknown] 4
dd;[unknown];[unknown] 4
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k] 4
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 5
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k];sys_write_[k];vfs_write_[k] 5
dd;[unknown];[unknown] 5
dd;[unknown];[unknown] 5
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k] 6
dd;read 15
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 19
dd;[unknown];__write;-;entry_SYSCALL_64_fastpath_[k] 20
dd;read;-;entry_SYSCALL_64_fastpath_[k] 23
dd;read;-;entry_SYSCALL_64_fastpath_[k];SyS_read_[k];vfs_read_[k];__vfs_read_[k];read_iter_zero_[k];iov_iter_zero_[k];__clear_user_[k] 24
dd;__write;-;entry_SYSCALL_64_fastpath_[k] 25
dd;__write 29
dd;[unknown];read;-;entry_SYSCALL_64_fastpath_[k] 31
This can be made into a flamegraph. Eg:
# ./profile -adf -p `pgrep -n func_ab` 10 > out.profile
# git clone https://github.com/brendangregg/FlameGraph
# ./FlameGraph/flamegraph.pl --color=java < out.profile > out.svg
It will highlight the kernel frames in orange, and user-level in red (and Java
in green, and C++ in yellow). If you copy-n-paste the above output into a
out.profile file, you can try it out.
You can increase or decrease the sample frequency. Eg, sampling at 9 Hertz:
# ./profile -F 9
Sampling at 9 Hertz of all threads by user + kernel stack... Hit Ctrl-C to end.
^C
[...]
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
1
[...]
You can also restrict profiling to just kernel stacks (-K) or user stacks (-U).
For example, just user stacks:
# ./profile -C 7 2
Sampling at 49 Hertz of all threads by user + kernel stack on CPU#7 for 2 secs.
PyEval_EvalFrameEx
[unknown]
[unknown]
- python (2827439)
1
PyDict_GetItem
[unknown]
- python (2827439)
1
[unknown]
- python (2827439)
1
PyEval_EvalFrameEx
[unknown]
[unknown]
- python (2827439)
1
PyEval_EvalFrameEx
- python (2827439)
1
[unknown]
[unknown]
- python (2827439)
in this example python application was busylooping on a single core/cpu (#7)
we were collecting stack traces only from it
# ./profile -U
Sampling at 49 Hertz of all threads by user stack... Hit Ctrl-C to end.
^C
[unknown]
[unknown]
- dd (2931)
1
[unknown]
[unknown]
- dd (2931)
1
[unknown]
[unknown]
- dd (2931)
1
[unknown]
[unknown]
- dd (2931)
1
[unknown]
[unknown]
- dd (2931)
1
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
1
[unknown]
- dd (2931)
1
[unknown]
- dd (2931)
1
func_a
main
__libc_start_main
[unknown]
- func_ab (2930)
3
__write
[unknown]
- dd (2931)
3
func_a
main
__libc_start_main
[unknown]
- func_ab (2930)
4
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
7
- swapper/6 (0)
10
func_b
main
__libc_start_main
[unknown]
- func_ab (2930)
10
__write
- dd (2931)
10
func_a
main
__libc_start_main
[unknown]
- func_ab (2930)
11
read
- dd (2931)
12
read
[unknown]
- dd (2931)
14
If there are too many unique stack traces for the kernel to save, a warning
will be printed. Eg:
# ./profile
[...]
WARNING: 8 stack traces could not be displayed. Consider increasing --stack-storage-size.
Run ./profile -h to see the default.
USAGE message:
# ./profile -h
usage: profile.py [-h] [-p PID | -L TID] [-U | -K] [-F FREQUENCY | -c COUNT] [-d] [-a]
[-I] [-f] [--stack-storage-size STACK_STORAGE_SIZE] [-C CPU]
[duration]
Profile CPU stack traces at a timed interval
positional arguments:
duration duration of trace, in seconds
optional arguments:
-h, --help show this help message and exit
-p PID, --pid PID profile process with this PID only
-L TID, --tid TID profile thread with this TID only
-U, --user-stacks-only
show stacks from user space only (no kernel space
stacks)
-K, --kernel-stacks-only
show stacks from kernel space only (no user space
stacks)
-F FREQUENCY, --frequency FREQUENCY
sample frequency, Hertz
-c COUNT, --count COUNT
sample period, number of events
-d, --delimited insert delimiter between kernel/user stacks
-a, --annotations add _[k] annotations to kernel frames
-I, --include-idle include CPU idle stacks
-f, --folded output folded format, one line per stack (for flame
graphs)
--stack-storage-size STACK_STORAGE_SIZE
the number of unique stack traces that can be stored
and displayed (default 16384)
-C CPU, --cpu CPU cpu number to run profile on
examples:
./profile # profile stack traces at 49 Hertz until Ctrl-C
./profile -F 99 # profile stack traces at 99 Hertz
./profile -c 1000000 # profile stack traces every 1 in a million events
./profile 5 # profile at 49 Hertz for 5 seconds only
./profile -f 5 # output in folded format for flame graphs
./profile -p 185 # only profile process with PID 185
./profile -L 185 # only profile thread with TID 185
./profile -U # only show user space stacks (no kernel)
./profile -K # only show kernel space stacks (no user)