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From: Andi Kleen <ak@linux.intel.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@redhat.com>, Ingo Molnar <mingo@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Stephane Eranian <eranian@google.com>,
	Ian Rogers <irogers@google.com>,
	Alexey Alexandrov <aalexand@google.com>
Subject: Re: [PATCH] perf/core: Emit PERF_RECORD_LOST for pinned events
Date: Mon, 18 Jan 2021 18:46:57 -0800	[thread overview]
Message-ID: <20210119024657.GA3526@tassilo.jf.intel.com> (raw)
In-Reply-To: <CAM9d7cg_Agin3C0iuigDzQjZEZNtVXPe9z9eaDZsdyNoVa_wxA@mail.gmail.com>

> > I don't think I object to having an even in the stream, but your LOST
> > event is unfortunate in that it itself can get lost when there's no
> > space in the buffer (which arguably is unlikely, but still).
> >
> > So from that point of view, I think overloading LOST is not so very nice
> > for this.
> 
> But anything can get lost in case of no space.
> Do you want to use something other than the LOST event?

Could always reserve the last entry in the ring buffer for a LOST event,
that would guarantee you can always get one out.

-Andi

  reply	other threads:[~2021-01-19  2:49 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-18  3:43 [PATCH] perf/core: Emit PERF_RECORD_LOST for pinned events Namhyung Kim
2021-01-18 10:11 ` Peter Zijlstra
2021-01-18 11:44   ` Namhyung Kim
2021-01-18 12:56     ` Peter Zijlstra
2021-01-19  1:42       ` Namhyung Kim
2021-01-19  2:46         ` Andi Kleen [this message]
2021-01-19  3:11           ` Namhyung Kim
2021-01-20 11:53             ` Namhyung Kim
2021-01-20 12:16               ` Arnaldo Carvalho de Melo

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