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author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2015-11-03 16:37:15 -0500 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2015-11-03 16:37:15 -0500 |
commit | 627645fdb657dfae5fcf26bbf6a6e1b63751dbc8 (patch) | |
tree | 7c8d356aa5ba5d77def07dd5859d848c94172131 | |
parent | 54ed1444052467044e9e01334ac8123dd6345211 (diff) | |
download | op-kernel-dev-627645fdb657dfae5fcf26bbf6a6e1b63751dbc8.zip op-kernel-dev-627645fdb657dfae5fcf26bbf6a6e1b63751dbc8.tar.gz |
tracing: Add some documentation about set_event_pid
Update Documentation to include some comments about how to use
set_event_pid.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r-- | Documentation/trace/events.txt | 18 | ||||
-rw-r--r-- | Documentation/trace/ftrace.txt | 6 |
2 files changed, 24 insertions, 0 deletions
diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt index 75d25a1..c010be8 100644 --- a/Documentation/trace/events.txt +++ b/Documentation/trace/events.txt @@ -288,6 +288,24 @@ prev_pid == 0 # cat sched_wakeup/filter common_pid == 0 +5.4 PID filtering +----------------- + +The set_event_pid file in the same directory as the top events directory +exists, will filter all events from tracing any task that does not have the +PID listed in the set_event_pid file. + +# cd /sys/kernel/debug/tracing +# echo $$ > set_event_pid +# echo 1 > events/enabled + +Will only trace events for the current task. + +To add more PIDs without losing the PIDs already included, use '>>'. + +# echo 123 244 1 >> set_event_pid + + 6. Event triggers ================= diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index db18362..f52f297 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -204,6 +204,12 @@ of ftrace. Here is a list of some of the key files: Have the function tracer only trace a single thread. + set_event_pid: + + Have the events only trace a task with a PID listed in this file. + Note, sched_switch and sched_wake_up will also trace events + listed in this file. + set_graph_function: Set a "trigger" function where tracing should start |