From: Namhyung Kim <namhyung@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
"Dr. David Alan Gilbert" <linux@treblig.org>,
Yang Li <yang.lee@linux.alibaba.com>,
James Clark <james.clark@linaro.org>,
Thomas Falcon <thomas.falcon@intel.com>,
Thomas Richter <tmricht@linux.ibm.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>,
Dapeng Mi <dapeng1.mi@linux.intel.com>
Subject: Re: [PATCH v5 1/3] perf stat: Read tool events last
Date: Wed, 19 Nov 2025 10:12:45 -0800 [thread overview]
Message-ID: <aR4IneHUTlFuyRhe@google.com> (raw)
In-Reply-To: <20251118211326.1840989-2-irogers@google.com>
On Tue, Nov 18, 2025 at 01:13:24PM -0800, Ian Rogers wrote:
> When reading a metric like memory bandwidth on multiple sockets, the
> additional sockets will be on CPUS > 0. Because of the affinity
> reading, the counters are read on CPU 0 along with the time, then the
> later sockets are read. This can lead to the later sockets having a
> bandwidth larger than is possible for the period of time. To avoid
> this move the reading of tool events to occur after all other events
> are read.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
Applied this one to perf-tools-next first, thanks!
Best regards,
Namhyung
next prev parent reply other threads:[~2025-11-19 18:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-18 21:13 [PATCH v5 0/3] perf stat affinity changes Ian Rogers
2025-11-18 21:13 ` [PATCH v5 1/3] perf stat: Read tool events last Ian Rogers
2025-11-19 18:12 ` Namhyung Kim [this message]
2025-11-18 21:13 ` [PATCH v5 2/3] perf evlist: Reduce affinity use and move into iterator, fix no affinity Ian Rogers
2025-11-18 21:13 ` [PATCH v5 3/3] perf stat: Add no-affinity flag Ian Rogers
2025-11-18 23:19 ` Andi Kleen
2025-11-19 0:58 ` Ian Rogers
2025-11-19 15:37 ` Andi Kleen
2025-11-19 16:25 ` Ian Rogers
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