linux-kernel - Re: [PATCH v2 0/4] perf: Make SIGTRAP and __perf_pending

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Message-ID: <ZfIJIfqeI9tWnnS5@x1>
Date: Wed, 13 Mar 2024 17:14:25 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Marco Elver <elver@...gle.com>, Vince Weaver <vincent.weaver@...ne.edu>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Ian Rogers <irogers@...gle.com>, Ingo Molnar <mingo@...hat.com>,
	Jiri Olsa <jolsa@...nel.org>, Mark Rutland <mark.rutland@....com>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v2 0/4] perf: Make SIGTRAP and __perf_pending_irq() work
 on RT.

On Wed, Mar 13, 2024 at 05:12:25PM -0300, Arnaldo Carvalho de Melo wrote:
> On Wed, Mar 13, 2024 at 03:30:52PM -0300, Arnaldo Carvalho de Melo wrote:
> > On Wed, Mar 13, 2024 at 03:14:28PM -0300, Arnaldo Carvalho de Melo wrote:
> > > 'perf test' doesn't show any regression, now I'm running Vince Weaver's
> > > https://github.com/deater/perf_event_tests, storing the results with
> > > this patchset and then without, to do a diff, lets see...

> > So things improved! I'll re-run to see if these results are stable...
 
> tldr; No dmesg activity, no kernel splats, most tests passed, nothing
> noticeable when running with/without the patch with Vince's regression
> tests. So:
 
> Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> Reported-by: Arnaldo Carvalho de Melo <acme@...hat.com>

Too quick, now I'm testing it on top of torvalds/master, no PREEMPT_RT.

- Arnaldo
 
> - Arnaldo
> 
> Further details:
> 
> Without the patch:
> 
> [root@...e perf_event_tests]# ./run_tests.sh | tee results.$(uname -r).new ; diff -u results.$(uname -r) results.$(uname -r).new
> --- results.6.8.0-rc7-rt6	2024-03-13 15:26:37.923323518 -0300
> +++ results.6.8.0-rc7-rt6.new	2024-03-13 15:32:43.983245095 -0300
> @@ -296,7 +296,7 @@
>    + tests/rdpmc/rdpmc_validation
>      Testing if userspace rdpmc reads give expected results...  PASSED
>    + tests/rdpmc/rdpmc_multiplexing
> -    Testing if userspace rdpmc multiplexing works...           PASSED
> +    Testing if userspace rdpmc multiplexing works...           FAILED
>    + tests/rdpmc/rdpmc_reset
>      Testing if resetting while using rdpmc works...            PASSED
>    + tests/rdpmc/rdpmc_group
> @@ -304,15 +304,15 @@
>    + tests/rdpmc/rdpmc_attach
>      Testing if rdpmc attach works...                           PASSED
>    + tests/rdpmc/rdpmc_attach_cpu
> -    Running on CPU 4
> +    Running on CPU 0
>  Testing if rdpmc behavior on attach CPU...                 PASSED
>    + tests/rdpmc/rdpmc_attach_global_cpu
> -    Running on CPU 6
> +    Running on CPU 3
>  Testing if rdpmc behavior on attach all procs on other CPU... FAILED
>    + tests/rdpmc/rdpmc_attach_other_cpu
> -    Measuring on CPU 5
> -Running on CPU 6
> -Measuring on CPU 5
> +    Measuring on CPU 0
> +Running on CPU 3
> +Measuring on CPU 0
>  Testing if rdpmc behavior on attach other CPU...           FAILED
>    + tests/rdpmc/rdpmc_multiattach
>      Testing if rdpmc multi-attach works...                     PASSED
> 
> A test flipped results.
> 
> Trying again with a more compact output:
> 
> [root@...e perf_event_tests]# ./run_tests.sh | tee results.$(uname -r).new ; diff -u results.$(uname -r) results.$(uname -r).new | grep ^[+-]
> --- results.6.8.0-rc7-rt6	2024-03-13 15:26:37.923323518 -0300
> +++ results.6.8.0-rc7-rt6.new	2024-03-13 17:06:34.944149451 -0300
> -    Running on CPU 4
> -Testing if rdpmc behavior on attach CPU...                 PASSED
> -  + tests/rdpmc/rdpmc_attach_global_cpu
> +Testing if rdpmc behavior on attach CPU...                 FAILED
> +  + tests/rdpmc/rdpmc_attach_global_cpu
> +    Running on CPU 0
> -    Measuring on CPU 5
> -Running on CPU 6
> -Measuring on CPU 5
> +    Measuring on CPU 7
> +Running on CPU 1
> +Measuring on CPU 7
> [root@...e perf_event_tests]#
> 
> Since its that rdpmc that is now always failing without this patch
> series, lets try using that .new as the new baseline:
> 
> [root@...e perf_event_tests]# ./run_tests.sh | tee results.$(uname -r).new2 ; diff -u results.$(uname -r).new results.$(uname -r).new2 | grep ^[+-]
> --- results.6.8.0-rc7-rt6.new	2024-03-13 17:06:34.944149451 -0300
> +++ results.6.8.0-rc7-rt6.new2	2024-03-13 17:08:41.438282558 -0300
> -    Testing "branch-misses" generalized event...               FAILED
> +    Testing "branch-misses" generalized event...               PASSED
> -    Testing if userspace rdpmc multiplexing works...           PASSED
> +    Testing if userspace rdpmc multiplexing works...           FAILED
> -    Running on CPU 6
> -Testing if rdpmc behavior on attach CPU...                 FAILED
> +    Running on CPU 2
> +Testing if rdpmc behavior on attach CPU...                 PASSED
> -    Running on CPU 0
> +    Running on CPU 2
> -    Measuring on CPU 7
> -Running on CPU 1
> -Measuring on CPU 7
> +    Measuring on CPU 2
> +Running on CPU 0
> +Measuring on CPU 2
> [root@...e perf_event_tests]#