| TRACE-CMD-PROFILE(1) | TRACE-CMD-PROFILE(1) |
trace-cmd-profile - profile tasks running live
trace-cmd profile [OPTIONS] [command]
The trace-cmd(1) profile will start tracing just like trace-cmd-record(1), with the --profile option, except that it does not write to a file, but instead, it will read the events as they happen and will update the accounting of the events. When the trace is finished, it will report the results just like trace-cmd-report(1) would do with its --profile option. In other words, the profile command does the work of trace-cmd record --profile, and trace-cmd report --profile without having to record the data to disk, in between.
The advantage of using the profile command is that the profiling can be done over a long period of time where recording all events would take up too much disk space.
This will enable several events as well as the function graph tracer with a depth of one (if the kernel supports it). This is to show where tasks enter and exit the kernel and how long they were in the kernel.
To disable calling function graph, use the -p option to enable another tracer. To not enable any tracer, use -p nop.
All timings are currently in nanoseconds.
These are the same as trace-cmd-record(1) with the --profile option.
-p tracer
-S
-G
-o file
-H event-hooks
The start_system:start_event (start_system is optional), is the event that starts the timing.
start_match is the field in the start event that is to match with the end_match in the end event.
start_pid is optional, as matches are attached to the tasks that run the events, if another field should be used to find that task, then it is specified with start_pid.
end_system:end_event is the event that ends the timing (end_system is optional).
end_match is the field in end_match that wil match the start event field start_match.
flags are optional and can be the following (case insensitive):
p : The two events are pinned to the same CPU (start and end happen
on the same CPU always).
s : The event should have a stack traced with it (enable stack tracing
for the start event).
g : The event is global (not associated to a task). start_pid is
not applicable with this flag.
--stderr
--- # trace-cmd profile -F sleep 1
[..] task: sleep-1121
Event: sched_switch:R (2) Total: 234559 Avg: 117279 Max: 129886 Min:104673
|
+ ftrace_raw_event_sched_switch (0xffffffff8109f310)
100% (2) time:234559 max:129886 min:104673 avg:117279
__schedule (0xffffffff816c1e81)
preempt_schedule (0xffffffff816c236e)
___preempt_schedule (0xffffffff81351a59)
|
+ unmap_single_vma (0xffffffff81198c05)
| 55% (1) time:129886 max:129886 min:0 avg:129886
| stop_one_cpu (0xffffffff8110909a)
| sched_exec (0xffffffff810a119b)
| do_execveat_common.isra.31 (0xffffffff811de528)
| do_execve (0xffffffff811dea8c)
| SyS_execve (0xffffffff811ded1e)
| return_to_handler (0xffffffff816c8458)
| stub_execve (0xffffffff816c6929)
|
+ unmap_single_vma (0xffffffff81198c05)
45% (1) time:104673 max:104673 min:0 avg:104673
unmap_vmas (0xffffffff81199174)
exit_mmap (0xffffffff811a1f5b)
mmput (0xffffffff8107699a)
flush_old_exec (0xffffffff811ddb75)
load_elf_binary (0xffffffff812287df)
search_binary_handler (0xffffffff811dd3e0)
do_execveat_common.isra.31 (0xffffffff811de8bd)
do_execve (0xffffffff811dea8c)
SyS_execve (0xffffffff811ded1e)
return_to_handler (0xffffffff816c8458)
stub_execve (0xffffffff816c6929)
Event: sched_switch:S (1) Total: 1000513242 Avg: 1000513242 Max: 1000513242 Min:1000513242
|
+ ftrace_raw_event_sched_switch (0xffffffff8109f310)
100% (1) time:1000513242 max:1000513242 min:0 avg:1000513242
__schedule (0xffffffff816c1e81)
schedule (0xffffffff816c23b9)
do_nanosleep (0xffffffff816c4f1c)
hrtimer_nanosleep (0xffffffff810dcd86)
SyS_nanosleep (0xffffffff810dcea6)
return_to_handler (0xffffffff816c8458)
tracesys_phase2 (0xffffffff816c65b0)
Event: sched_wakeup:1121 (1) Total: 43405 Avg: 43405 Max: 43405 Min:43405
|
+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (1) time:43405 max:43405 min:0 avg:43405
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
wake_up_process (0xffffffff810a4057)
hrtimer_wakeup (0xffffffff810db772)
__run_hrtimer (0xffffffff810dbd91)
hrtimer_interrupt (0xffffffff810dc6b7)
local_apic_timer_interrupt (0xffffffff810363e7)
smp_trace_apic_timer_interrupt (0xffffffff816c8c6a)
trace_apic_timer_interrupt (0xffffffff816c725a)
finish_task_switch (0xffffffff8109c3a4)
__schedule (0xffffffff816c1e01)
schedule (0xffffffff816c23b9)
ring_buffer_wait (0xffffffff811323a3)
wait_on_pipe (0xffffffff81133d93)
tracing_buffers_splice_read (0xffffffff811350b0)
do_splice_to (0xffffffff8120476f)
SyS_splice (0xffffffff81206c1f)
tracesys_phase2 (0xffffffff816c65b0)
Event: func: sys_nanosleep() (1) Total: 1000598016 Avg: 1000598016 Max: 1000598016 Min:1000598016 Event: func: sys_munmap() (1) Total: 14300 Avg: 14300 Max: 14300 Min:14300 Event: func: sys_arch_prctl() (1) Total: 571 Avg: 571 Max: 571 Min:571 Event: func: sys_mprotect() (4) Total: 14382 Avg: 3595 Max: 7196 Min:2190 Event: func: SyS_read() (1) Total: 2640 Avg: 2640 Max: 2640 Min:2640 Event: func: sys_close() (5) Total: 4001 Avg: 800 Max: 1252 Min:414 Event: func: sys_newfstat() (3) Total: 11684 Avg: 3894 Max: 10206 Min:636 Event: func: SyS_open() (3) Total: 23615 Avg: 7871 Max: 10535 Min:4743 Event: func: sys_access() (1) Total: 5924 Avg: 5924 Max: 5924 Min:5924 Event: func: SyS_mmap() (8) Total: 39153 Avg: 4894 Max: 12354 Min:1518 Event: func: smp_trace_apic_timer_interrupt() (1) Total: 10298 Avg: 10298 Max: 10298 Min:10298 Event: func: SyS_brk() (4) Total: 2407 Avg: 601 Max: 1564 Min:206 Event: func: do_notify_resume() (2) Total: 4095 Avg: 2047 Max: 2521 Min:1574 Event: func: sys_execve() (5) Total: 1625251 Avg: 325050 Max: 1605698 Min:3570
|
+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (1) time:1605698 max:1605698 min:0 avg:1605698
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
wake_up_process (0xffffffff810a4057)
cpu_stop_queue_work (0xffffffff81108df8)
stop_one_cpu (0xffffffff8110909a)
sched_exec (0xffffffff810a119b)
do_execveat_common.isra.31 (0xffffffff811de528)
do_execve (0xffffffff811dea8c)
SyS_execve (0xffffffff811ded1e)
return_to_handler (0xffffffff816c8458)
stub_execve (0xffffffff816c6929)
stub_execve (0xffffffff816c6929)
Event: func: syscall_trace_enter_phase2() (38) Total: 21544 Avg: 566 Max: 1066 Min:329 Event: func: syscall_trace_enter_phase1() (38) Total: 9202 Avg: 242 Max: 376 Min:150 Event: func: __do_page_fault() (53) Total: 257672 Avg: 4861 Max: 27745 Min:458
|
+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (1) time:27745 max:27745 min:0 avg:27745
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
default_wake_function (0xffffffff810a4002)
autoremove_wake_function (0xffffffff810b50fd)
__wake_up_common (0xffffffff810b4958)
__wake_up (0xffffffff810b4cb8)
rb_wake_up_waiters (0xffffffff8112f126)
irq_work_run_list (0xffffffff81157d0f)
irq_work_run (0xffffffff81157d5e)
smp_trace_irq_work_interrupt (0xffffffff810082fc)
trace_irq_work_interrupt (0xffffffff816c7aaa)
return_to_handler (0xffffffff816c8458)
trace_do_page_fault (0xffffffff810478b2)
trace_page_fault (0xffffffff816c7dd2)
Event: func: syscall_trace_leave() (38) Total: 26145 Avg: 688 Max: 1264 Min:381 Event: func: __sb_end_write() (1) Total: 373 Avg: 373 Max: 373 Min:373 Event: func: fsnotify() (1) Total: 598 Avg: 598 Max: 598 Min:598 Event: func: __fsnotify_parent() (1) Total: 286 Avg: 286 Max: 286 Min:286 Event: func: mutex_unlock() (2) Total: 39636 Avg: 19818 Max: 39413 Min:223 Event: func: smp_trace_irq_work_interrupt() (6) Total: 236459 Avg: 39409 Max: 100671 Min:634
|
+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (4) time:234348 max:100671 min:38745 avg:58587
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
default_wake_function (0xffffffff810a4002)
autoremove_wake_function (0xffffffff810b50fd)
__wake_up_common (0xffffffff810b4958)
__wake_up (0xffffffff810b4cb8)
rb_wake_up_waiters (0xffffffff8112f126)
irq_work_run_list (0xffffffff81157d0f)
irq_work_run (0xffffffff81157d5e)
smp_trace_irq_work_interrupt (0xffffffff810082fc)
return_to_handler (0xffffffff816c8458)
trace_irq_work_interrupt (0xffffffff816c7aaa)
|
+ ftrace_return_to_handler (0xffffffff81140840)
| 84% (3) time:197396 max:100671 min:38745 avg:65798
| return_to_handler (0xffffffff816c846d)
| trace_page_fault (0xffffffff816c7dd2)
|
+ ftrace_return_to_handler (0xffffffff81140840)
16% (1) time:36952 max:36952 min:0 avg:36952
ftrace_graph_caller (0xffffffff816c8428)
mutex_unlock (0xffffffff816c3f75)
rb_simple_write (0xffffffff81133142)
vfs_write (0xffffffff811d7727)
SyS_write (0xffffffff811d7acf)
tracesys_phase2 (0xffffffff816c65b0)
Event: sys_enter:35 (1) Total: 1000599765 Avg: 1000599765 Max: 1000599765 Min:1000599765 Event: sys_enter:11 (1) Total: 55025 Avg: 55025 Max: 55025 Min:55025 Event: sys_enter:158 (1) Total: 1584 Avg: 1584 Max: 1584 Min:1584 Event: sys_enter:10 (4) Total: 18359 Avg: 4589 Max: 8764 Min:2933 Event: sys_enter:0 (1) Total: 4223 Avg: 4223 Max: 4223 Min:4223 Event: sys_enter:3 (5) Total: 9948 Avg: 1989 Max: 2606 Min:1203 Event: sys_enter:5 (3) Total: 15530 Avg: 5176 Max: 11840 Min:1405 Event: sys_enter:2 (3) Total: 28002 Avg: 9334 Max: 12035 Min:5656 Event: sys_enter:21 (1) Total: 7814 Avg: 7814 Max: 7814 Min:7814 Event: sys_enter:9 (8) Total: 49583 Avg: 6197 Max: 14137 Min:2362 Event: sys_enter:12 (4) Total: 108493 Avg: 27123 Max: 104079 Min:922 Event: sys_enter:59 (5) Total: 1631608 Avg: 326321 Max: 1607529 Min:4563 Event: page_fault_user:0x398d86b630 (1) Event: page_fault_user:0x398d844de0 (1) Event: page_fault_user:0x398d8d9020 (1) Event: page_fault_user:0x1d37008 (1) Event: page_fault_user:0x7f0b89e91074 (1) Event: page_fault_user:0x7f0b89d98ed0 (1) Event: page_fault_user:0x7f0b89ec8950 (1) Event: page_fault_user:0x7f0b89d83644 (1) Event: page_fault_user:0x7f0b89d622a8 (1) Event: page_fault_user:0x7f0b89d5a560 (1) Event: page_fault_user:0x7f0b89d34010 (1) Event: page_fault_user:0x1d36008 (1) Event: page_fault_user:0x398d900510 (1) Event: page_fault_user:0x398dbb3ae8 (1) Event: page_fault_user:0x398d87f490 (1) Event: page_fault_user:0x398d8eb660 (1) Event: page_fault_user:0x398d8bd730 (1) Event: page_fault_user:0x398d9625d9 (1) Event: page_fault_user:0x398d931810 (1) Event: page_fault_user:0x398dbb7114 (1) Event: page_fault_user:0x398d837610 (1) Event: page_fault_user:0x398d89e860 (1) Event: page_fault_user:0x398d8f23b0 (1) Event: page_fault_user:0x398dbb4510 (1) Event: page_fault_user:0x398dbad6f0 (1) Event: page_fault_user:0x398dbb1018 (1) Event: page_fault_user:0x398d977b37 (1) Event: page_fault_user:0x398d92eb60 (1) Event: page_fault_user:0x398d8abff0 (1) Event: page_fault_user:0x398dbb0d30 (1) Event: page_fault_user:0x398dbb6c24 (1) Event: page_fault_user:0x398d821c50 (1) Event: page_fault_user:0x398dbb6c20 (1) Event: page_fault_user:0x398d886350 (1) Event: page_fault_user:0x7f0b90125000 (1) Event: page_fault_user:0x7f0b90124740 (1) Event: page_fault_user:0x7f0b90126000 (1) Event: page_fault_user:0x398d816230 (1) Event: page_fault_user:0x398d8002b8 (1) Event: page_fault_user:0x398dbb0b40 (1) Event: page_fault_user:0x398dbb2880 (1) Event: page_fault_user:0x7f0b90141cc6 (1) Event: page_fault_user:0x7f0b9013b85c (1) Event: page_fault_user:0x7f0b90127000 (1) Event: page_fault_user:0x606e70 (1) Event: page_fault_user:0x7f0b90144010 (1) Event: page_fault_user:0x7fffcb31b038 (1) Event: page_fault_user:0x606da8 (1) Event: page_fault_user:0x400040 (1) Event: page_fault_user:0x398d222218 (1) Event: page_fault_user:0x398d015120 (1) Event: page_fault_user:0x398d220ce8 (1) Event: page_fault_user:0x398d220b80 (1) Event: page_fault_user:0x7fffcb2fcff8 (1) Event: page_fault_user:0x398d001590 (1) Event: page_fault_user:0x398d838490 (1) Event: softirq_raise:RCU (3) Total: 252931 Avg: 84310 Max: 243288 Min:4639 Event: softirq_raise:SCHED (2) Total: 241249 Avg: 120624 Max: 239076 Min:2173
|
+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (1) time:239076 max:239076 min:0 avg:239076
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
default_wake_function (0xffffffff810a4002)
autoremove_wake_function (0xffffffff810b50fd)
__wake_up_common (0xffffffff810b4958)
__wake_up (0xffffffff810b4cb8)
rb_wake_up_waiters (0xffffffff8112f126)
irq_work_run_list (0xffffffff81157d0f)
irq_work_run (0xffffffff81157d5e)
smp_trace_irq_work_interrupt (0xffffffff810082fc)
trace_irq_work_interrupt (0xffffffff816c7aaa)
irq_exit (0xffffffff8107dd66)
smp_trace_apic_timer_interrupt (0xffffffff816c8c7a)
trace_apic_timer_interrupt (0xffffffff816c725a)
prepare_ftrace_return (0xffffffff8103d4fd)
ftrace_graph_caller (0xffffffff816c8428)
mem_cgroup_begin_page_stat (0xffffffff811cfd25)
page_remove_rmap (0xffffffff811a4fc5)
stub_execve (0xffffffff816c6929)
unmap_single_vma (0xffffffff81198b1c)
unmap_vmas (0xffffffff81199174)
exit_mmap (0xffffffff811a1f5b)
mmput (0xffffffff8107699a)
flush_old_exec (0xffffffff811ddb75)
load_elf_binary (0xffffffff812287df)
search_binary_handler (0xffffffff811dd3e0)
do_execveat_common.isra.31 (0xffffffff811de8bd)
do_execve (0xffffffff811dea8c)
SyS_execve (0xffffffff811ded1e)
return_to_handler (0xffffffff816c8458)
Event: softirq_raise:HI (3) Total: 72472 Avg: 24157 Max: 64186 Min:3430 Event: softirq_entry:RCU (2) Total: 3191 Avg: 1595 Max: 1788 Min:1403
|
+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (1) time:1788 max:1788 min:0 avg:1788
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
default_wake_function (0xffffffff810a4002)
autoremove_wake_function (0xffffffff810b50fd)
__wake_up_common (0xffffffff810b4958)
__wake_up (0xffffffff810b4cb8)
rb_wake_up_waiters (0xffffffff8112f126)
irq_work_run_list (0xffffffff81157d0f)
irq_work_run (0xffffffff81157d5e)
smp_trace_irq_work_interrupt (0xffffffff810082fc)
trace_irq_work_interrupt (0xffffffff816c7aaa)
irq_work_queue (0xffffffff81157e95)
ring_buffer_unlock_commit (0xffffffff8113039f)
__buffer_unlock_commit (0xffffffff811367d5)
trace_buffer_unlock_commit (0xffffffff811376a2)
ftrace_event_buffer_commit (0xffffffff81146d5f)
ftrace_raw_event_sched_process_exec (0xffffffff8109c511)
do_execveat_common.isra.31 (0xffffffff811de9a3)
do_execve (0xffffffff811dea8c)
SyS_execve (0xffffffff811ded1e)
return_to_handler (0xffffffff816c8458)
stub_execve (0xffffffff816c6929)
Event: softirq_entry:SCHED (2) Total: 2289 Avg: 1144 Max: 1350 Min:939
Event: softirq_entry:HI (3) Total: 180146 Avg: 60048 Max: 178969 Min:499
|
+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (1) time:178969 max:178969 min:0 avg:178969
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
wake_up_process (0xffffffff810a4057)
wake_up_worker (0xffffffff8108de74)
insert_work (0xffffffff8108fca6)
__queue_work (0xffffffff8108fe12)
delayed_work_timer_fn (0xffffffff81090088)
call_timer_fn (0xffffffff810d8f89)
run_timer_softirq (0xffffffff810da8a1)
__do_softirq (0xffffffff8107d8fa)
irq_exit (0xffffffff8107dd66)
smp_trace_apic_timer_interrupt (0xffffffff816c8c7a)
trace_apic_timer_interrupt (0xffffffff816c725a)
prepare_ftrace_return (0xffffffff8103d4fd)
ftrace_graph_caller (0xffffffff816c8428)
mem_cgroup_begin_page_stat (0xffffffff811cfd25)
page_remove_rmap (0xffffffff811a4fc5)
stub_execve (0xffffffff816c6929)
unmap_single_vma (0xffffffff81198b1c)
unmap_vmas (0xffffffff81199174)
exit_mmap (0xffffffff811a1f5b)
mmput (0xffffffff8107699a)
flush_old_exec (0xffffffff811ddb75)
load_elf_binary (0xffffffff812287df)
search_binary_handler (0xffffffff811dd3e0)
do_execveat_common.isra.31 (0xffffffff811de8bd)
do_execve (0xffffffff811dea8c)
SyS_execve (0xffffffff811ded1e)
return_to_handler (0xffffffff816c8458) ---
The above uses -F to follow the sleep task. It filters only on events that pertain to sleep. Note, in order to follow forks, you need to also include the -c flag.
Other tasks will appear in the profile as well if events reference more than one task (like sched_switch and sched_wakeup do. The "prev_pid" and "next_pid" of sched_switch, and the "common_pid" and "pid" of sched_wakeup).
Stack traces are attached to events that are related to them.
Taking a look at the above output:
Event: sched_switch:R (2) Total: 234559 Avg: 117279 Max: 129886 Min:104673
This shows that task was preempted (it’s in the running R state). It was preempted twice (2) for a total of 234,559 nanoseconds, with a average preempt time of 117,279 ns, and maximum of 128,886 ns and minimum of 104,673 ns.
The tree shows where it was preempted:
| + ftrace_raw_event_sched_switch (0xffffffff8109f310)
100% (2) time:234559 max:129886 min:104673 avg:117279
__schedule (0xffffffff816c1e81)
preempt_schedule (0xffffffff816c236e)
___preempt_schedule (0xffffffff81351a59)
|
+ unmap_single_vma (0xffffffff81198c05)
| 55% (1) time:129886 max:129886 min:0 avg:129886
| stop_one_cpu (0xffffffff8110909a)
| sched_exec (0xffffffff810a119b)
| do_execveat_common.isra.31 (0xffffffff811de528)
| do_execve (0xffffffff811dea8c)
| SyS_execve (0xffffffff811ded1e)
| return_to_handler (0xffffffff816c8458)
| stub_execve (0xffffffff816c6929)
|
+ unmap_single_vma (0xffffffff81198c05)
45% (1) time:104673 max:104673 min:0 avg:104673
unmap_vmas (0xffffffff81199174)
exit_mmap (0xffffffff811a1f5b)
mmput (0xffffffff8107699a)
flush_old_exec (0xffffffff811ddb75)
load_elf_binary (0xffffffff812287df)
search_binary_handler (0xffffffff811dd3e0)
do_execveat_common.isra.31 (0xffffffff811de8bd)
do_execve (0xffffffff811dea8c)
SyS_execve (0xffffffff811ded1e)
return_to_handler (0xffffffff816c8458)
stub_execve (0xffffffff816c6929)
Event: sched_switch:S (1) Total: 1000513242 Avg: 1000513242 Max: 1000513242 Min:10005132
This shows that the task was scheduled out in the INTERRUPTIBLE state once for a total of 1,000,513,242 ns (~1s), which makes sense as the task was a "sleep 1".
After the schedule events, the function events are shown. By default the profiler will use the function graph tracer if the depth setting is supported by the kernel. It will set the depth to one which will only trace the first function that enters the kernel. It will also record the amount of time it was in the kernel.
Event: func: sys_nanosleep() (1) Total: 1000598016 Avg: 1000598016 Max: 1000598016 Min:1000598016 Event: func: sys_munmap() (1) Total: 14300 Avg: 14300 Max: 14300 Min:14300 Event: func: sys_arch_prctl() (1) Total: 571 Avg: 571 Max: 571 Min:571 Event: func: sys_mprotect() (4) Total: 14382 Avg: 3595 Max: 7196 Min:2190 Event: func: SyS_read() (1) Total: 2640 Avg: 2640 Max: 2640 Min:2640 Event: func: sys_close() (5) Total: 4001 Avg: 800 Max: 1252 Min:414 Event: func: sys_newfstat() (3) Total: 11684 Avg: 3894 Max: 10206 Min:636 Event: func: SyS_open() (3) Total: 23615 Avg: 7871 Max: 10535 Min:4743 Event: func: sys_access() (1) Total: 5924 Avg: 5924 Max: 5924 Min:5924 Event: func: SyS_mmap() (8) Total: 39153 Avg: 4894 Max: 12354 Min:1518 Event: func: smp_trace_apic_timer_interrupt() (1) Total: 10298 Avg: 10298 Max: 10298 Min:10298 Event: func: SyS_brk() (4) Total: 2407 Avg: 601 Max: 1564 Min:206 Event: func: do_notify_resume() (2) Total: 4095 Avg: 2047 Max: 2521 Min:1574 Event: func: sys_execve() (5) Total: 1625251 Avg: 325050 Max: 1605698 Min:3570
Count of times the event was hit is always in parenthesis (5).
The function graph trace may produce too much overhead as it is still triggering (just not tracing) on all functions. To limit functions just to system calls (not interrupts), add the following option:
-l 'sys_*' -l 'SyS_*'
To disable function graph tracing totally, use:
-p nop
To use function tracing instead (note, this will not record timings, but just the count of times a function is hit):
-p function
Following the functions are the events that are recorded.
Event: sys_enter:35 (1) Total: 1000599765 Avg: 1000599765 Max: 1000599765 Min:1000599765 Event: sys_enter:11 (1) Total: 55025 Avg: 55025 Max: 55025 Min:55025 Event: sys_enter:158 (1) Total: 1584 Avg: 1584 Max: 1584 Min:1584 Event: sys_enter:10 (4) Total: 18359 Avg: 4589 Max: 8764 Min:2933 Event: sys_enter:0 (1) Total: 4223 Avg: 4223 Max: 4223 Min:4223 Event: sys_enter:3 (5) Total: 9948 Avg: 1989 Max: 2606 Min:1203 Event: sys_enter:5 (3) Total: 15530 Avg: 5176 Max: 11840 Min:1405 Event: sys_enter:2 (3) Total: 28002 Avg: 9334 Max: 12035 Min:5656 Event: sys_enter:21 (1) Total: 7814 Avg: 7814 Max: 7814 Min:7814 Event: sys_enter:9 (8) Total: 49583 Avg: 6197 Max: 14137 Min:2362 Event: sys_enter:12 (4) Total: 108493 Avg: 27123 Max: 104079 Min:922 Event: sys_enter:59 (5) Total: 1631608 Avg: 326321 Max: 1607529 Min:4563
These are the raw system call events, with the raw system call ID after the "sys_enter:" For example, "59" is execve(2). Why did it execute 5 times? Looking at a strace of this run, we can see:
execve("/usr/lib64/ccache/sleep", ["sleep", "1"], [/* 27 vars */] <unfinished ...>
<... execve resumed> ) = -1 ENOENT (No such file or directory)
execve("/usr/local/sbin/sleep", ["sleep", "1"], [/* 27 vars */] <unfinished ...>
<... execve resumed> ) = -1 ENOENT (No such file or directory)
execve("/usr/local/bin/sleep", ["sleep", "1"], [/* 27 vars */] <unfinished ...>
<... execve resumed> ) = -1 ENOENT (No such file or directory)
execve("/usr/sbin/sleep", ["sleep", "1"], [/* 27 vars */] <unfinished ...>
<... execve resumed> ) = -1 ENOENT (No such file or directory)
execve("/usr/bin/sleep", ["sleep", "1"], [/* 27 vars */] <unfinished ...>
<... execve resumed> ) = 0
It attempted to execve the "sleep" command for each path in $PATH until it found one.
The page_fault_user events show what userspace address took a page fault.
Event: softirq_raise:RCU (3) Total: 252931 Avg: 84310 Max: 243288 Min:4639 Event: softirq_raise:SCHED (2) Total: 241249 Avg: 120624 Max: 239076 Min:2173
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+ ftrace_raw_event_sched_wakeup_template (0xffffffff8109d960)
100% (1) time:239076 max:239076 min:0 avg:239076
ttwu_do_wakeup (0xffffffff810a01a2)
ttwu_do_activate.constprop.122 (0xffffffff810a0236)
try_to_wake_up (0xffffffff810a3ec3)
default_wake_function (0xffffffff810a4002)
autoremove_wake_function (0xffffffff810b50fd)
__wake_up_common (0xffffffff810b4958)
__wake_up (0xffffffff810b4cb8)
rb_wake_up_waiters (0xffffffff8112f126)
irq_work_run_list (0xffffffff81157d0f)
irq_work_run (0xffffffff81157d5e)
smp_trace_irq_work_interrupt (0xffffffff810082fc)
trace_irq_work_interrupt (0xffffffff816c7aaa)
irq_exit (0xffffffff8107dd66)
The timings for the softirq_raise events measure the time it took from the raised softirq to the time it executed.
The timings for the softirq_entry events measure the time the softirq took to execute.
The stack traces for the softirqs (and possibly other events) are used when an event has a stack attached to it. This can happen if the profile ran more stacks than just the sched events, or when events are dropped and stacks
To have full control of what gets traced, use the -S option that will have trace-cmd not enable any events or the function_graph tracer. Only the events listed on the command line are shown.
If only the time of kmalloc is needed to be seen, and where it was recorded, using the -S option and enabling function_graph and stack tracing for just the function needed will give the profile of only that function.
--- # trace-cmd profile -S -p function_graph -l '*kmalloc*' -l '*kmalloc*:stacktrace' sleep 1 task: sshd-11786
Event: func: __kmalloc_reserve.isra.59() (2) Total: 149684 Avg: 74842 Max: 75598 Min:74086
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+ __alloc_skb (0xffffffff815a8917)
| 67% (2) time:149684 max:75598 min:74086 avg:74842
| __kmalloc_node_track_caller (0xffffffff811c6635)
| __kmalloc_reserve.isra.59 (0xffffffff815a84ac)
| return_to_handler (0xffffffff816c8458)
| sk_stream_alloc_skb (0xffffffff81604ea1)
| tcp_sendmsg (0xffffffff8160592c)
| inet_sendmsg (0xffffffff8162fed1)
| sock_aio_write (0xffffffff8159f9fc)
| do_sync_write (0xffffffff811d694a)
| vfs_write (0xffffffff811d7825)
| SyS_write (0xffffffff811d7adf)
| system_call_fastpath (0xffffffff816c63d2)
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+ __alloc_skb (0xffffffff815a8917)
33% (1) time:74086 max:74086 min:74086 avg:74086
__alloc_skb (0xffffffff815a8917)
sk_stream_alloc_skb (0xffffffff81604ea1)
tcp_sendmsg (0xffffffff8160592c)
inet_sendmsg (0xffffffff8162fed1)
sock_aio_write (0xffffffff8159f9fc)
do_sync_write (0xffffffff811d694a)
vfs_write (0xffffffff811d7825)
SyS_write (0xffffffff811d7adf)
system_call_fastpath (0xffffffff816c63d2)
[..] ---
To watch the command run but save the output of the profile to a file use --stderr, and redirect stderr to a file
# trace-cmd profile --stderr cyclictest -p 80 -n -t1 2> profile.out
Or simple use -o
# trace-cmd profile -o profile.out cyclictest -p 80 -n -t1
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1), trace-cmd-stop(1), trace-cmd-reset(1), trace-cmd-split(1), trace-cmd-list(1), trace-cmd-listen(1)
Written by Steven Rostedt, <rostedt@goodmis.org[1]>
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
Copyright (C) 2014 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).
| 08/19/2020 |