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| author | Tom Zanussi <tom.zanussi@linux.intel.com> | 2016-03-03 21:54:55 +0300 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2016-04-20 01:55:57 +0300 |
| commit | d0bad49bb0a094a1beb06640785f95cb256b7272 (patch) | |
| tree | bbcba1655873c597ce50844c5aad99230100b240 /kernel/trace/trace.c | |
| parent | 6a475cb17fe161dbde62eca7e4c2cf59edff182f (diff) | |
| download | linux-d0bad49bb0a094a1beb06640785f95cb256b7272.tar.xz | |
tracing: Add enable_hist/disable_hist triggers
Similar to enable_event/disable_event triggers, these triggers enable
and disable the aggregation of events into maps rather than enabling
and disabling their writing into the trace buffer.
They can be used to automatically start and stop hist triggers based
on a matching filter condition.
If there's a paused hist trigger on system:event, the following would
start it when the filter condition was hit:
# echo enable_hist:system:event [ if filter] > event/trigger
And the following would disable a running system:event hist trigger:
# echo disable_hist:system:event [ if filter] > event/trigger
See Documentation/trace/events.txt for real examples.
Link: http://lkml.kernel.org/r/f812f086e52c8b7c8ad5443487375e03c96a601f.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2238bfde799b..8430145bea12 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3807,6 +3807,10 @@ static const char readme_msg[] = "\t trigger: traceon, traceoff\n" "\t enable_event:<system>:<event>\n" "\t disable_event:<system>:<event>\n" +#ifdef CONFIG_HIST_TRIGGERS + "\t enable_hist:<system>:<event>\n" + "\t disable_hist:<system>:<event>\n" +#endif #ifdef CONFIG_STACKTRACE "\t\t stacktrace\n" #endif @@ -3867,6 +3871,10 @@ static const char readme_msg[] = "\t The 'clear' parameter will clear the contents of a running\n" "\t hist trigger and leave its current paused/active state\n" "\t unchanged.\n\n" + "\t The enable_hist and disable_hist triggers can be used to\n" + "\t have one event conditionally start and stop another event's\n" + "\t already-attached hist trigger. The syntax is analagous to\n" + "\t the enable_event and disable_event triggers.\n" #endif ; |