diff options
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/events.txt | 18 | ||||
| -rw-r--r-- | Documentation/trace/ftrace.txt | 23 |
2 files changed, 41 insertions, 0 deletions
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 ef621d34ba5b..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 @@ -2437,6 +2443,23 @@ The following commands are supported: echo '!writeback*:mod:ext3' >> set_ftrace_filter + Mod command supports module globbing. Disable tracing for all + functions except a specific module: + + echo '!*:mod:!ext3' >> set_ftrace_filter + + Disable tracing for all modules, but still trace kernel: + + echo '!*:mod:*' >> set_ftrace_filter + + Enable filter only for kernel: + + echo '*write*:mod:!*' >> set_ftrace_filter + + Enable filter for module globbing: + + echo '*write*:mod:*snd*' >> set_ftrace_filter + - traceon/traceoff These commands turn tracing on and off when the specified functions are hit. The parameter determines how many times the |