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The -D/--graph-depth option is to set max graph depth. The following
example traces max 2-depth of page fault handler.
$ sudo perf ftrace -G __do_page_fault -D 2 -- hello
...
0) | __do_page_fault() {
0) 0.063 us | down_read_trylock();
0) 0.251 us | find_vma();
0) 5.374 us | handle_mm_fault();
0) 0.054 us | up_read();
0) 7.463 us | }
...
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170618142302.25390-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The -T/--trace-funcs and -N/--notrace-funcs options are to specify
functions to enable/disable tracing dynamically.
The -G/--graph-funcs and -g/--nograph-funcs options are to set filters
for function graph tracer.
For example, to trace fault handling functions only:
$ sudo perf ftrace -T *fault hello
0) | __do_page_fault() {
0) | handle_mm_fault() {
0) 2.117 us | __handle_mm_fault();
0) 3.627 us | }
0) 7.811 us | }
0) | __do_page_fault() {
0) | handle_mm_fault() {
0) 2.014 us | __handle_mm_fault();
0) 2.424 us | }
0) 2.951 us | }
...
To trace all functions executed in __do_page_fault:
$ sudo perf ftrace -G __do_page_fault hello
2) | __do_page_fault() {
3) 0.060 us | down_read_trylock();
3) | find_vma() {
3) 0.075 us | vmacache_find();
3) 0.053 us | vmacache_update();
3) 1.246 us | }
3) | handle_mm_fault() {
3) 0.063 us | __rcu_read_lock();
3) 0.056 us | mem_cgroup_from_task();
3) 0.057 us | __rcu_read_unlock();
3) | __handle_mm_fault() {
3) | filemap_map_pages() {
3) 0.058 us | __rcu_read_lock();
3) | alloc_set_pte() {
...
But don't want to show details in handle_mm_fault:
$ sudo perf ftrace -G __do_page_fault -g handle_mm_fault hello
3) | __do_page_fault() {
3) 0.049 us | down_read_trylock();
3) | find_vma() {
3) 0.048 us | vmacache_find();
3) 0.041 us | vmacache_update();
3) 0.680 us | }
3) 0.036 us | up_read();
3) 4.547 us | } /* __do_page_fault */
...
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170618142302.25390-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The -a/--all-cpus and -C/--cpu option is for controlling tracing cpus.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170224011251.14946-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The -p (--pid) option enables to trace existing process by its pid.
Committer notes:
Testing it:
Using the function_graph tracer on a process that is just waiting for user
input and thus will make 'perf ftrace' sit there waiting for that, then press
any key on that mutt session and see what happens:
# perf ftrace -t function_graph -p `pidof mutt` | head -40
2) 1.038 us | switch_mm_irqs_off();
------------------------------------------
2) <idle>-0 => mutt-3595
------------------------------------------
2) | finish_task_switch() {
2) | smp_irq_work_interrupt() {
2) | irq_enter() {
2) 0.180 us | rcu_irq_enter();
2) 1.248 us | }
2) | __wake_up() {
2) 0.126 us | _raw_spin_lock_irqsave();
2) | __wake_up_common() {
2) | pollwake() {
2) | default_wake_function() {
2) | try_to_wake_up() {
2) 0.662 us | _raw_spin_lock_irqsave();
2) | select_task_rq_fair() {
2) 1.719 us | effective_load.isra.41();
2) 1.343 us | effective_load.isra.41();
2) | select_idle_sibling() {
2) 0.331 us | idle_cpu();
2) 1.458 us | }
2) 8.350 us | }
2) 0.200 us | _raw_spin_lock();
2) | ttwu_do_activate() {
2) | activate_task() {
2) 0.136 us | update_rq_clock.part.77();
2) | enqueue_task_fair() {
2) | enqueue_entity() {
2) 0.146 us | update_curr();
2) 0.330 us | account_entity_enqueue();
2) 0.280 us | update_cfs_shares();
2) 0.321 us | place_entity();
2) 0.206 us | __enqueue_entity();
2) 6.926 us | }
2) | enqueue_entity() {
2) 0.105 us | update_curr();
2) 0.175 us | account_entity_enqueue();
2) 0.531 us | update_cfs_shares();
#
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170224011251.14946-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The 'perf ftrace' command is a simple wrapper of kernel's ftrace
functionality. It only supports single thread tracing currently and
just reads trace_pipe in text and then write it to stdout.
Committer notes:
Testing it:
# perf ftrace -f function_graph usleep 123456
<SNIP>
2) | SyS_nanosleep() {
2) | _copy_from_user() {
<SNIP>
2) 0.900 us | }
2) 1.354 us | }
2) | hrtimer_nanosleep() {
2) 0.062 us | __hrtimer_init();
2) | do_nanosleep() {
2) | hrtimer_start_range_ns() {
<SNIP>
2) 5.025 us | }
2) | schedule() {
2) 0.125 us | rcu_note_context_switch();
2) 0.057 us | _raw_spin_lock();
2) | deactivate_task() {
2) 0.369 us | update_rq_clock.part.77();
2) | dequeue_task_fair() {
<SNIP>
2) + 22.453 us | }
2) + 23.736 us | }
2) | pick_next_task_fair() {
<SNIP>
2) + 47.167 us | }
2) | pick_next_task_idle() {
<SNIP>
2) 4.462 us | }
------------------------------------------
2) usleep-20387 => <idle>-0
------------------------------------------
2) 0.806 us | switch_mm_irqs_off();
------------------------------------------
2) <idle>-0 => usleep-20387
------------------------------------------
2) 0.151 us | finish_task_switch();
2) @ 123597.2 us | }
2) 0.037 us | _cond_resched();
2) | hrtimer_try_to_cancel() {
2) 0.064 us | hrtimer_active();
2) 0.353 us | }
2) @ 123605.3 us | }
2) @ 123606.2 us | }
2) @ 123608.3 us | } /* SyS_nanosleep */
2) | __do_page_fault() {
<SNIP>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremy Eder <jeder@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-r1hgmsj4dxny8arn3o9mw512@git.kernel.org
[ Various foward port fixes, add man page ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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