linux-kernel - Re: [PATCH 0/4] perf arm-spe: Improve --itrace options

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Message-ID: <aL9HvOl-n_IM0qiB@x1>
Date: Mon, 8 Sep 2025 18:16:44 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: James Clark <james.clark@...aro.org>
Cc: John Garry <john.g.garry@...cle.com>, Will Deacon <will@...nel.org>,
	Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...ux.dev>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	George Wort <George.Wort@....com>,
	Graham Woodward <Graham.Woodward@....com>,
	Ben Gainey <Ben.Gainey@....com>,
	Michael Williams <Michael.Williams@....com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/4] perf arm-spe: Improve --itrace options

On Mon, Sep 08, 2025 at 01:10:17PM +0100, James Clark wrote:
> Most people also want all the SPE samples (instructions group), not just
> the flagged samples that are put into the various memory groups. These
> should have been shown by default but weren't because the default
> interval type wasn't supported.
> 
> Also when looking at this, it appears that the downsampling was behaving
> in a way that would discard samples from one group but not another.
> Improve that and the warning messages.
> 
> I don't want to put fixes tags on these because it's only changing the
> defaults and the behavior, but I don't think the previous behavior was
> incorrect necessarily, just copied from tracing techs but not ideal for
> SPE.

I keep trying to find some hardware to have in my homelab to test these
series, but till then I depend on people having access to such hardware
for acks or better, tested-by, so waiting a bit for those to appear.

- Arnaldo
 
> Signed-off-by: James Clark <james.clark@...aro.org>
> ---
> James Clark (4):
>       perf arm-spe: Show instruction sample types by default
>       perf arm-spe: Downsample all sample types equally
>       perf arm-spe: Display --itrace period warnings for all sample types
>       perf docs: Update SPE doc to include default instructions group
> 
>  tools/perf/Documentation/perf-arm-spe.txt | 14 +++++---
>  tools/perf/util/arm-spe.c                 | 53 ++++++++++++++++---------------
>  2 files changed, 37 insertions(+), 30 deletions(-)
> ---
> base-commit: 75a7b9d29215c5aa813b9620f3c56817918f9f8c
> change-id: 20250908-james-perf-spe-period-4711a566cba4
> 
> Best regards,
> -- 
> James Clark <james.clark@...aro.org>
>