tracing: Add enable_hist/disable_hist triggers

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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>

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This commit is contained in:

Tom Zanussi 2016-03-03 12:54:55 -06:00 • committed by Steven Rostedt

parent 6a475cb17f

commit d0bad49bb0

5 changed files with 196 additions and 31 deletions

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1

include/linux/trace_events.h

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8

kernel/trace/trace.c

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32

kernel/trace/trace.h

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115

kernel/trace/trace_events_hist.c

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71

kernel/trace/trace_events_trigger.c

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