From: Namhyung Kim <namhyung@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: 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>,
Andi Kleen <ak@linux.intel.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 20:44:20 +0900 [thread overview]
Message-ID: <CAM9d7cgr+Vxq_SnEkSO5zU0QN-X6-LLJDKUfE4C72Nomnrr=+Q@mail.gmail.com> (raw)
In-Reply-To: <YAVezkTtAkIAImzx@hirez.programming.kicks-ass.net>
Hi Peter,
On Mon, Jan 18, 2021 at 7:11 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Mon, Jan 18, 2021 at 12:43:23PM +0900, Namhyung Kim wrote:
> > As of now we silently ignore pinned events when it's failed to be
> > scheduled and make it error state not try to schedule it again.
> > That means we won't get any samples for the event.
> >
> > But there's no way for users to notice and respond to it. Let's
> > emit a lost event with a new misc bit to indicate this situation.
>
> Users should get a read(2) error IIRC, does that not work?
Ah, right. maybe I'm too specific to perf record's perspective.
In perf record, it doesn't use read(2) so I thought it should
have the information in the stream of sample data.
Thanks,
Namhyung
next prev parent reply other threads:[~2021-01-18 14:19 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 [this message]
2021-01-18 12:56 ` Peter Zijlstra
2021-01-19 1:42 ` Namhyung Kim
2021-01-19 2:46 ` Andi Kleen
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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