Messages in this thread | | | Date | Wed, 10 Apr 2024 15:58:40 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v3 3/4] perf: Remove perf_swevent_get_recursion_context() from perf_pending_task(). |
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Le Wed, Apr 10, 2024 at 02:51:26PM +0200, Sebastian Andrzej Siewior a écrit : > On 2024-04-10 12:38:50 [+0200], Frederic Weisbecker wrote: > > Some alternatives: > > > > _ Clear event->pending_work = 0 after perf_sigtrap(), preventing an > > event in there from adding a new task work. We may miss a signal though... > > > > _ Make the recursion context per task on -RT... > > The per-task counter would be indeed the easiest thing to do. But then > only for task context, right?
It should work for CPU context as well. A context switch shouldn't be considered as recursion. Hopefully...
> > But why would we miss a signal if we clean event->pending_work late? > Isn't cleaning late same as clearing in > perf_swevent_put_recursion_context()?
Not exactly. perf_swevent_get_recursion_context() avoids a new software event altogether from being recorded. It is completely ignored. Whereas clearing late event->pending_work records new software events but ignores the signal.
> If clearing pending_work late works, I would prefer to avoid yet another > per-task counter if possible.
Yeah I know :-/
Thanks.
> > > > > Thanks. > > Sebastian
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