From: Peter Zijlstra <peterz@infradead.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@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>,
Michael Petlan <mpetlan@redhat.com>, Jiri Olsa <jolsa@redhat.com>
Subject: Re: [PATCH v4] perf/core: Add a new read format to get a number of lost samples
Date: Fri, 17 Jun 2022 14:53:48 +0200 [thread overview]
Message-ID: <Yqx5XPluXje13Ez/@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20220616180623.1358843-1-namhyung@kernel.org>
On Thu, Jun 16, 2022 at 11:06:23AM -0700, Namhyung Kim wrote:
> Sometimes we want to know an accurate number of samples even if it's
> lost. Currenlty PERF_RECORD_LOST is generated for a ring-buffer which
> might be shared with other events. So it's hard to know per-event
> lost count.
>
> Add event->lost_samples field and PERF_FORMAT_LOST to retrieve it from
> userspace.
>
> Original-patch-by: Jiri Olsa <jolsa@redhat.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
Looks OK I suppose. Bit sad to get an unconditional atomic on the lost
path, but then again, we shouldn't be hitting that in the first place.
Thanks!
next prev parent reply other threads:[~2022-06-17 12:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-16 18:06 Namhyung Kim
2022-06-17 12:53 ` Peter Zijlstra [this message]
2022-06-28 7:16 ` [tip: perf/core] " tip-bot2 for Namhyung Kim
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