linux-kernel - Re: [PATCH v4 00/10] perf stat fixes and improvements

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Message-ID: <aRy0SVVuZaTfY3xU@google.com>
Date: Tue, 18 Nov 2025 10:00:41 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	"Dr. David Alan Gilbert" <linux@...blig.org>,
	Yang Li <yang.lee@...ux.alibaba.com>,
	James Clark <james.clark@...aro.org>,
	Thomas Falcon <thomas.falcon@...el.com>,
	Thomas Richter <tmricht@...ux.ibm.com>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	Andi Kleen <ak@...ux.intel.com>,
	Dapeng Mi <dapeng1.mi@...ux.intel.com>
Subject: Re: [PATCH v4 00/10] perf stat fixes and improvements

On Thu, Nov 13, 2025 at 10:05:06AM -0800, Ian Rogers wrote:
> A collection of fixes aiming to stabilize and make more reasonable
> measurements/metrics such as memory bandwidth.
> 
> Tool events are changed from getting a PMU cpu map of all online CPUs
> to either CPU 0 or all online CPUs. This avoids iterating over useless
> CPUs for events in particular `duration_time`. Fix a bug where
> duration_time didn't correctly use the previous raw counts and would
> skip values in interval mode.
> 
> Change how json metrics handle tool events. Use the counter value
> rather than using shared state with perf stat. A later patch changes
> it so that tool events are read last, so that if reading say memory
> bandwidth counters you don't divide by an earlier read time and exceed
> the theoretical maximum memory bandwidth.

[...]

Applied the first 7 patches to perf-tools-next, thanks!

Best regards,
Namhyung