Messages in this thread | | | Date | Mon, 27 Mar 2023 14:37:11 +0200 | Subject | Re: Enable histograms for events/ftrace/timerlat and osnoise | From | Daniel Bristot de Oliveira <> |
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On 3/24/23 17:13, Daniel Bristot de Oliveira wrote: > Hi Steven > > I would like to collect histograms from timerlat and osnoise tracers event, > but I cannot collect them because they are not tracepoints but... tracer > events. So... > > # ls /sys/kernel/tracing/events/ftrace/timerlat/ > format hist > > no hist, filter, trigger files...
Ooop, the hist file exists, what is missing is the trigger file, which is used to enable the histogram...
it seems that the "limitation" is around TRACE_EVENT_FL_IGNORE_ENABLE flag, and the fact that ftrace events cannot be enabled/disabled...
but wait, as the hist file exist, is there any other way to enable the histogram? (or should we disable hist files for !TRACE_EVENT_FL_IGNORE_ENABLE)?
am I missing something?
> How hard would it be to enable histograms to the ftrace/osnoise and > ftrace/timerlat events? > > This will allow me to reduce the overhead of rtla timerlat and rtla osnoise > tools... > > Thanks in advance, Stephen! > -- Denny
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