-
Notifications
You must be signed in to change notification settings - Fork 3.9k
/
offcputime_example.txt
773 lines (684 loc) · 19.2 KB
/
offcputime_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
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
Demonstrations of offcputime, the Linux eBPF/bcc version.
This program shows stack traces that were blocked, and the total duration they
were blocked. It works by tracing when threads block and when they return to
CPU, measuring both the time they were blocked (aka the "off-CPU time") and the
blocked stack trace and the task name. This data is summarized in kernel by
summing the blocked time by unique stack trace and task name.
Here is some example output. The -K option was used to only match kernel stacks.
To explain what we are seeing: the very first stack trace looks like a page
fault (do_page_fault() etc) from the "chmod" command, and in total was off-CPU
for 13 microseconds.
# ./offcputime -K
Tracing off-CPU time (us) of all threads by kernel stack... Hit Ctrl-C to end.
^C
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
wait_on_page_bit_killable
__lock_page_or_retry
filemap_fault
__do_fault
handle_mm_fault
__do_page_fault
do_page_fault
page_fault
chmod
13
schedule
rcu_nocb_kthread
kthread
ret_from_fork
ddebug_tables
rcuos/0
22
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit_lock
__lock_page
lock_page
__do_fault
handle_mm_fault
__do_page_fault
do_page_fault
page_fault
run
27
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
wait_on_page_bit_killable
__lock_page_or_retry
filemap_fault
__do_fault
handle_mm_fault
__do_page_fault
do_page_fault
page_fault
clear_user
padzero
load_elf_binary
search_binary_handler
load_script
search_binary_handler
do_execveat_common.isra.27
run
28
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
wait_on_page_bit_killable
__lock_page_or_retry
filemap_fault
__do_fault
handle_mm_fault
__do_page_fault
do_page_fault
page_fault
run
82
schedule
pipe_wait
pipe_read
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
bash
94
schedule
rcu_gp_kthread
kthread
ret_from_fork
ddebug_tables
rcu_sched
104
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
out_of_line_wait_on_bit
__wait_on_buffer
jbd2_journal_commit_transaction
kjournald2
kthread
ret_from_fork
mb_cache_list
jbd2/xvda1-8
986
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
out_of_line_wait_on_bit
__wait_on_buffer
jbd2_journal_commit_transaction
kjournald2
kthread
ret_from_fork
mb_cache_list
jbd2/xvda1-8
6630
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
out_of_line_wait_on_bit
do_get_write_access
jbd2_journal_get_write_access
__ext4_journal_get_write_access
ext4_mb_mark_diskspace_used
ext4_mb_new_blocks
ext4_ext_map_blocks
ext4_map_blocks
ext4_writepages
do_writepages
__filemap_fdatawrite_range
filemap_flush
ext4_alloc_da_blocks
ext4_rename
ext4_rename2
supervise
6645
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
out_of_line_wait_on_bit
do_get_write_access
jbd2_journal_get_write_access
__ext4_journal_get_write_access
__ext4_new_inode
ext4_create
vfs_create
path_openat
do_filp_open
do_sys_open
sys_open
entry_SYSCALL_64_fastpath
supervise
12702
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/2
16036
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/4
24085
schedule
do_wait
sys_wait4
entry_SYSCALL_64_fastpath
run
233055
schedule
schedule_timeout
io_schedule_timeout
bit_wait_io
__wait_on_bit
wait_on_page_bit
truncate_inode_pages_range
truncate_inode_pages_final
ext4_evict_inode
evict
iput
__dentry_kill
dput
sys_rename
entry_SYSCALL_64_fastpath
supervise
297113
schedule
schedule_timeout
wait_woken
n_tty_read
tty_read
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
bash
1789866
schedule
schedule_timeout
io_schedule_timeout
do_blockdev_direct_IO
__blockdev_direct_IO
blkdev_direct_IO
generic_file_read_iter
blkdev_read_iter
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
dd
3310763
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/1
3999989
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/5
3999995
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/4
3999996
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/0
3999996
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/3
3999998
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/7
3999999
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/2
4000001
schedule
smpboot_thread_fn
kthread
ret_from_fork
watchdog/6
4000001
schedule
do_wait
sys_wait4
entry_SYSCALL_64_fastpath
bash
4039675
schedule
do_nanosleep
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath
svscan
5000112
schedule
schedule_hrtimeout_range_clock
schedule_hrtimeout_range
poll_schedule_timeout
do_select
core_sys_select
sys_select
entry_SYSCALL_64_fastpath
snmpd
5998761
schedule
smpboot_thread_fn
kthread
ret_from_fork
migration/3
6149779
schedule
schedule_hrtimeout_range_clock
schedule_hrtimeout_range
poll_schedule_timeout
do_select
core_sys_select
sys_select
entry_SYSCALL_64_fastpath
ntpd
6999832
schedule
worker_thread
kthread
ret_from_fork
kworker/u16:2
7131941
schedule
worker_thread
kthread
ret_from_fork
kworker/3:0
7999844
schedule
worker_thread
kthread
ret_from_fork
kworker/1:1
7999872
schedule
worker_thread
kthread
ret_from_fork
kworker/2:1
7999889
schedule
worker_thread
kthread
ret_from_fork
kworker/5:1
7999936
schedule
worker_thread
kthread
ret_from_fork
kworker/7:1
7999938
schedule
worker_thread
kthread
ret_from_fork
kworker/6:1
7999940
schedule
do_nanosleep
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath
tail
8000905
schedule
smpboot_thread_fn
kthread
ret_from_fork
migration/7
8197046
schedule
pipe_wait
pipe_read
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
readproctitle
8197835
schedule
smpboot_thread_fn
kthread
ret_from_fork
migration/4
8201851
schedule
smpboot_thread_fn
kthread
ret_from_fork
migration/2
8203375
schedule
smpboot_thread_fn
kthread
ret_from_fork
migration/6
8208664
schedule
smpboot_thread_fn
kthread
ret_from_fork
migration/5
8209819
schedule
smpboot_thread_fn
kthread
ret_from_fork
ddebug_tables
migration/0
8211292
schedule
smpboot_thread_fn
kthread
ret_from_fork
migration/1
8212100
schedule
worker_thread
kthread
ret_from_fork
kworker/0:2
8270305
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/3
8349697
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/2
8363357
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/1
8365338
schedule
schedule_timeout
xfs_buf_terminate
kthread
ret_from_fork
xfsaild/md0
8371514
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/4
8384013
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/5
8390016
schedule
rcu_nocb_kthread
kthread
ret_from_fork
ddebug_tables
rcuos/0
8405428
schedule
schedule_timeout
rcu_gp_kthread
kthread
ret_from_fork
ddebug_tables
rcu_sched
8406930
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/7
8409575
schedule
rcu_nocb_kthread
kthread
ret_from_fork
rcuos/6
8415062
schedule
schedule_hrtimeout_range_clock
schedule_hrtimeout_range
poll_schedule_timeout
do_select
core_sys_select
sys_select
entry_SYSCALL_64_fastpath
offcputime
8421478
schedule
worker_thread
kthread
ret_from_fork
kworker/4:0
8421492
schedule
schedule_hrtimeout_range_clock
schedule_hrtimeout_range
poll_schedule_timeout
do_select
core_sys_select
sys_select
entry_SYSCALL_64_fastpath
sshd
14249005
schedule
schedule_hrtimeout_range_clock
schedule_hrtimeout_range
poll_schedule_timeout
do_sys_poll
sys_poll
entry_SYSCALL_64_fastpath
supervise
81670888
The last few stack traces aren't very interesting, since they are threads that
are often blocked off-CPU waiting for work.
Do be somewhat careful with overhead: this is tracing scheduler functions, which
can be called very frequently. While this uses in-kernel summaries for
efficiency, the rate of scheduler functions can be very high (> 1,000,000/sec),
and this is performing stack walks when threads return to CPU. At some point
the overhead will be measurable.
A -p option can be used to filter (in-kernel) on a single process ID. For
example, only matching PID 26651, which is a running "dd" command:
# ./offcputime -K -p 26651
Tracing off-CPU time (us) of all threads by kernel stack... Hit Ctrl-C to end.
^C
schedule
schedule_timeout
io_schedule_timeout
do_blockdev_direct_IO
__blockdev_direct_IO
blkdev_direct_IO
generic_file_read_iter
blkdev_read_iter
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
dd
2405710
The stack trace shows "dd" is blocked waiting on disk I/O, as expected, for a
total of 2.4 seconds during tracing.
A duration can be added, for example, tracing for 5 seconds only:
# ./offcputime -K -p 26651 5
Tracing off-CPU time (us) of all threads by kernel stack for 5 secs.
schedule
schedule_timeout
io_schedule_timeout
do_blockdev_direct_IO
__blockdev_direct_IO
blkdev_direct_IO
generic_file_read_iter
blkdev_read_iter
__vfs_read
vfs_read
sys_read
entry_SYSCALL_64_fastpath
dd
4413909
Here, dd was blocked for 4.4 seconds out of 5. Or put differently, likely
on-CPU for about 12% of the time. Which matches the ratio seen by time(1):
# time dd if=/dev/md0 iflag=direct of=/dev/null bs=1k
^C108115+0 records in
108114+0 records out
110708736 bytes (111 MB) copied, 13.7565 s, 8.0 MB/s
real 0m13.760s
user 0m0.000s
sys 0m1.739s
A -f option will emit output using the "folded stacks" format, which can be
read directly by flamegraph.pl from the FlameGraph open source software
(https://github.com/brendangregg/FlameGraph). Eg:
# ./offcputime -K -f 5
bash;entry_SYSCALL_64_fastpath;sys_read;vfs_read;__vfs_read;tty_read;n_tty_read;call_rwsem_down_read_failed;rwsem_down_read_failed;schedule 8
yes;entry_SYSCALL_64_fastpath;sys_write;vfs_write;__vfs_write;tty_write;n_tty_write;call_rwsem_down_read_failed;rwsem_down_read_failed;schedule 14
run;page_fault;do_page_fault;__do_page_fault;handle_mm_fault;__do_fault;filemap_fault;__lock_page_or_retry;wait_on_page_bit_killable;__wait_on_bit;bit_wait_io;io_schedule_timeout;schedule_timeout;schedule 33
rcuos/4;ret_from_fork;kthread;rcu_nocb_kthread;schedule 45
bash;entry_SYSCALL_64_fastpath;sys_read;vfs_read;__vfs_read;pipe_read;pipe_wait;schedule 88
run;page_fault;do_page_fault;__do_page_fault;handle_mm_fault;__do_fault;filemap_fault;__lock_page_or_retry;wait_on_page_bit_killable;__wait_on_bit;bit_wait_io;io_schedule_timeout;schedule_timeout;schedule 108
jbd2/xvda1-8;mb_cache_list;ret_from_fork;kthread;kjournald2;jbd2_journal_commit_transaction;__wait_on_buffer;out_of_line_wait_on_bit;__wait_on_bit;bit_wait_io;io_schedule_timeout;schedule_timeout;schedule 828
jbd2/xvda1-8;mb_cache_list;ret_from_fork;kthread;kjournald2;jbd2_journal_commit_transaction;__wait_on_buffer;out_of_line_wait_on_bit;__wait_on_bit;bit_wait_io;io_schedule_timeout;schedule_timeout;schedule 6201
supervise;entry_SYSCALL_64_fastpath;sys_rename;dput;__dentry_kill;iput;evict;ext4_evict_inode;truncate_inode_pages_final;truncate_inode_pages_range;wait_on_page_bit;__wait_on_bit;bit_wait_io;io_schedule_timeout;schedule_timeout;schedule 41049
run;entry_SYSCALL_64_fastpath;sys_wait4;do_wait;schedule 120709
bash;entry_SYSCALL_64_fastpath;sys_wait4;do_wait;schedule 699320
ksoftirqd/0;ret_from_fork;kthread;smpboot_thread_fn;schedule 1077529
bash;entry_SYSCALL_64_fastpath;sys_read;vfs_read;__vfs_read;tty_read;n_tty_read;wait_woken;schedule_timeout;schedule 1362045
sshd;entry_SYSCALL_64_fastpath;sys_select;core_sys_select;do_select;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule 1377627
migration/0;ddebug_tables;ret_from_fork;kthread;smpboot_thread_fn;schedule 2040753
snmpd;entry_SYSCALL_64_fastpath;sys_select;core_sys_select;do_select;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule 2197568
migration/5;ret_from_fork;kthread;smpboot_thread_fn;schedule 3079426
migration/7;ret_from_fork;kthread;smpboot_thread_fn;schedule 3084746
kworker/6:2;ret_from_fork;kthread;worker_thread;schedule 3940583
kworker/5:1;ret_from_fork;kthread;worker_thread;schedule 3944892
kworker/1:2;ret_from_fork;kthread;worker_thread;schedule 3999646
ntpd;entry_SYSCALL_64_fastpath;sys_select;core_sys_select;do_select;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule 3999904
kworker/u16:0;ret_from_fork;kthread;worker_thread;schedule 3999967
kworker/7:0;ret_from_fork;kthread;worker_thread;schedule 3999987
tail;entry_SYSCALL_64_fastpath;sys_nanosleep;hrtimer_nanosleep;do_nanosleep;schedule 4000473
migration/1;ret_from_fork;kthread;smpboot_thread_fn;schedule 4091150
migration/4;ret_from_fork;kthread;smpboot_thread_fn;schedule 4095217
readproctitle;entry_SYSCALL_64_fastpath;sys_read;vfs_read;__vfs_read;pipe_read;pipe_wait;schedule 4108470
migration/3;ret_from_fork;kthread;smpboot_thread_fn;schedule 4109264
migration/2;ret_from_fork;kthread;smpboot_thread_fn;schedule 4109280
migration/6;ret_from_fork;kthread;smpboot_thread_fn;schedule 4111143
kworker/4:0;ret_from_fork;kthread;worker_thread;schedule 4402350
kworker/3:0;ret_from_fork;kthread;worker_thread;schedule 4433988
kworker/2:1;ret_from_fork;kthread;worker_thread;schedule 4636142
kworker/0:2;ret_from_fork;kthread;worker_thread;schedule 4832023
rcuos/1;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4974186
rcuos/5;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4977137
rcuos/6;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4987769
rcuos/3;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4992282
rcuos/4;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4992364
rcuos/2;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4992714
rcuos/0;ddebug_tables;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4996504
rcuos/7;ret_from_fork;kthread;rcu_nocb_kthread;schedule 4998497
rcu_sched;ddebug_tables;ret_from_fork;kthread;rcu_gp_kthread;schedule_timeout;schedule 5000686
offcputime;entry_SYSCALL_64_fastpath;sys_select;core_sys_select;do_select;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule 5005063
dd;entry_SYSCALL_64_fastpath;sys_read;vfs_read;__vfs_read;blkdev_read_iter;generic_file_read_iter;blkdev_direct_IO;__blockdev_direct_IO;do_blockdev_direct_IO;io_schedule_timeout;schedule_timeout;schedule 8025599
supervise;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule 40835611
The stack traces are shown as single lines, with functions separated by
semicolons. The first entry is the task name. The 2nd column is the total
off-CPU time.
I'd save this output to a file, then move it to the system where you'll be
creating your "off-CPU time flame graphs".
USAGE message:
# ./offcputime.py -h
usage: offcputime.py [-h] [-p PID | -t TID | -u | -k] [-U | -K] [-d] [-f] [-s]
[--stack-storage-size STACK_STORAGE_SIZE]
[-m MIN_BLOCK_TIME] [-M MAX_BLOCK_TIME] [--state STATE]
[duration]
Summarize off-CPU time by stack trace
positional arguments:
duration duration of trace, in seconds
optional arguments:
-h, --help show this help message and exit
-p PID, --pid PID trace this PID only
-t TID, --tid TID trace this TID only
-u, --user-threads-only
user threads only (no kernel threads)
-k, --kernel-threads-only
kernel threads only (no user threads)
-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)
-d, --delimited insert delimiter between kernel/user stacks
-f, --folded output folded format
-s, --offset show address offsets
--stack-storage-size STACK_STORAGE_SIZE
the number of unique stack traces that can be stored
and displayed (default 16384)
-m MIN_BLOCK_TIME, --min-block-time MIN_BLOCK_TIME
the amount of time in microseconds over which we store
traces (default 1)
-M MAX_BLOCK_TIME, --max-block-time MAX_BLOCK_TIME
the amount of time in microseconds under which we
store traces (default U64_MAX)
--state STATE filter on this thread state bitmask (eg, 2 ==
TASK_UNINTERRUPTIBLE) see include/linux/sched.h
examples:
./offcputime # trace off-CPU stack time until Ctrl-C
./offcputime 5 # trace for 5 seconds only
./offcputime -f 5 # 5 seconds, and output in folded format
./offcputime -s 5 # 5 seconds, and show symbol offsets
./offcputime -m 1000 # trace only events that last more than 1000 usec
./offcputime -M 10000 # trace only events that last less than 10000 usec
./offcputime -p 185 # only trace threads for PID 185
./offcputime -t 188 # only trace thread 188
./offcputime -u # only trace user threads (no kernel)
./offcputime -k # only trace kernel threads (no user)
./offcputime -U # only show user space stacks (no kernel)
./offcputime -K # only show kernel space stacks (no user)