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Message-ID: <8734uwxrca.wl-maz@kernel.org>
Date: Wed, 17 Jan 2024 09:05:25 +0000
From: Marc Zyngier <maz@...nel.org>
To: Mark Rutland <mark.rutland@....com>
Cc: linux-kernel@...r.kernel.org,
Hector Martin <marcan@...can.st>,
Ian Rogers <irogers@...gle.com>,
acme@...hat.com,
james.clark@....com,
john.g.garry@...cle.com,
leo.yan@...aro.org,
linux-arm-kernel@...ts.infradead.org,
linux-perf-users@...r.kernel.org,
mike.leach@...aro.org,
namhyung@...nel.org,
suzuki.poulose@....com,
tmricht@...ux.ibm.com,
will@...nel.org
Subject: Re: [PATCH] perf print-events: make is_event_supported() more robust
Hi Mark,
On Tue, 16 Jan 2024 17:03:48 +0000,
Mark Rutland <mark.rutland@....com> wrote:
>
> Currently the perf tool doesn't deteect support for extneded event types
> on Apple M1/M2 systems, and will not auto-expand plain PERF_EVENT_TYPE
> hardware events into per-PMU events. This is due to the detection of
> extended event types not handling mandatory filters required by the
> M1/M2 PMU driver.
Thanks for looking into this.
I've given your patch a go on my M1 box, and it indeed makes things
substantially better:
$ sudo ./perf stat -e cycles ~/hackbench 100 process 1000
Running with 100*40 (== 4000) tasks.
Time: 3.419
Performance counter stats for '/home/maz/hackbench 100 process 1000':
174,783,472,090 apple_firestorm_pmu/cycles/ (93.10%)
39,134,744,813 apple_icestorm_pmu/cycles/ (71.86%)
3.568145595 seconds time elapsed
12.203084000 seconds user
55.135271000 seconds sys
However, I'm seeing some slightly odd behaviours:
$ sudo ./perf stat -e cycles:k ~/hackbench 100 process 1000
Running with 100*40 (== 4000) tasks.
Time: 3.313
Performance counter stats for '/home/maz/hackbench 100 process 1000':
<not supported> apple_firestorm_pmu/cycles:k/
<not supported> apple_icestorm_pmu/cycles:k/
3.467568841 seconds time elapsed
13.080111000 seconds user
53.162099000 seconds sys
I would have expected it to count, but it didn't. For that to work, I
have to add the 'H' modifier:
$ sudo ./perf stat -e cycles:Hk ~/hackbench 100 process 1000
Running with 100*40 (== 4000) tasks.
Time: 3.335
Performance counter stats for '/home/maz/hackbench 100 process 1000':
183,756,134,397 apple_firestorm_pmu/cycles:Hk/ (85.56%)
37,302,841,991 apple_icestorm_pmu/cycles:Hk/ (72.10%)
3.490138958 seconds time elapsed
13.376772000 seconds user
53.326289000 seconds sys
But my perf-foo is as basic as it gets, so it is likely that I'm
missing something.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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