Messages in this thread | | | Date | Mon, 27 Mar 2023 11:27:15 -0400 | From | Steven Rostedt <> | Subject | Re: Enable histograms for events/ftrace/timerlat and osnoise |
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On Mon, 27 Mar 2023 14:37:11 +0200 Daniel Bristot de Oliveira <bristot@redhat.com> wrote:
> 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)?
No, I think we just missed not creating the "hist" file, which should not actually exist.
> > am I missing something? > > > How hard would it be to enable histograms to the ftrace/osnoise and > > ftrace/timerlat events?
I'll try to get some time to look at this. No guarantees :-p
-- Steve
> > > > This will allow me to reduce the overhead of rtla timerlat and rtla osnoise > > tools... > > > > Thanks in advance, Stephen! > > -- Denny
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