From: "Steven Rostedt (Red Hat)" <[email protected]> Update Documentation to include some comments about how to use set_event_pid.
Signed-off-by: Steven Rostedt <[email protected]> --- Documentation/trace/events.txt | 18 ++++++++++++++++++ Documentation/trace/ftrace.txt | 6 ++++++ 2 files changed, 24 insertions(+) diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt index 75d25a1d6e42..c010be8c85d7 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 db18362c14f3..f52f297cb406 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 -- 2.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
