Re: [PATCH v11 22/28] tracing: Add enable_hist/disable_hist triggers

From: Namhyung Kim
Date: Tue Nov 03 2015 - 03:56:14 EST

On Thu, Oct 22, 2015 at 01:14:26PM -0500, Tom Zanussi wrote:
> 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

What about named hist triggers? Maybe worth adding
"enable/disable_hist_name" too?


> See Documentation/trace/events.txt for real examples.
> Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
> Tested-by: Masami Hiramatsu <>
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