Hi Steve, On Tue, 2019-05-07 at 20:11 -0400, Steven Rostedt wrote: > Tom, > > Can you review this patch. > Sure. > Jon, > > After Tom gives his review, can you take this in your tree? > > Thanks! > > Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> > Reviewed-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx> Thanks, Tom > -- Steve > > > On Tue, 7 May 2019 17:49:46 +0300 > Tzvetomir Stoyanov <tstoyanov@xxxxxxxxxx> wrote: > > > The current trace documentation, the section describing histogram's > > "onmatch" > > is not straightforward enough about how this action is applied. It > > is not > > clear what criteria are used to "match" both events. A short note > > is added, > > describing what exactly is compared in order to match the events. > > > > Signed-off-by: Tzvetomir Stoyanov <tstoyanov@xxxxxxxxxx> > > --- > > Documentation/trace/histogram.txt | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/Documentation/trace/histogram.txt > > b/Documentation/trace/histogram.txt > > index 7ffea6aa22e3..d97f0530a731 100644 > > --- a/Documentation/trace/histogram.txt > > +++ b/Documentation/trace/histogram.txt > > @@ -1863,7 +1863,10 @@ hist trigger specification. > > > > The 'matching.event' specification is simply the fully > > qualified > > event name of the event that matches the target event for the > > - onmatch() functionality, in the form 'system.event_name'. > > + onmatch() functionality, in the form 'system.event_name'. > > Histogram > > + keys of both events are compared to find if events match. In > > the case > > + multiple histogram keys are used, both events must have the > > same > > + number of keys, and the keys must match in the same order. > > > > Finally, the number and type of variables/fields in the 'param > > list' must match the number and types of the fields in the > > @@ -1920,9 +1923,10 @@ hist trigger specification. > > /sys/kernel/debug/tracing/events/sched/sched_waking/tr > > igger > > > > Then, when the corresponding thread is actually scheduled onto > > the > > - CPU by a sched_switch event, calculate the latency and use > > that > > - along with another variable and an event field to generate a > > - wakeup_latency synthetic event: > > + CPU by a sched_switch event (where the sched_waking key > > "saved_pid" > > + matches the sched_switch key "next_pid"), calculate the > > latency and > > + use that along with another variable and an event field to > > generate > > + a wakeup_latency synthetic event: > > > > # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs- > > $ts0:\ > > onmatch(sched.sched_waking).wakeup_latency($wakeup_lat > > ,\ > >
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