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From: Peter Zijlstra <peterz@infradead.org>
To: Ganapatrao Kulkarni <gklkml16@gmail.com>
Cc: Ian Rogers <irogers@google.com>, Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Kan Liang <kan.liang@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Stephane Eranian <eranian@google.com>,
	Ganapatrao Kulkarni <gkulkarni@marvell.com>,
	Jayachandran Chandrasekharan Nair <jnair@marvell.com>
Subject: Re: [PATCH] perf cgroups: Don't rotate events for cgroups unnecessarily
Date: Fri, 23 Aug 2019 13:59:46 +0200	[thread overview]
Message-ID: <20190823115946.GM2349@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKTKpr6m7YzqJ7U2icNHq7ZwoG0pw8ws_EHcLR+-T6ZeEfe15Q@mail.gmail.com>


A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

On Fri, Aug 23, 2019 at 04:13:46PM +0530, Ganapatrao Kulkarni wrote:

> We are seeing regression with our uncore perf driver(Marvell's
> ThunderX2, ARM64 server platform) on 5.3-Rc1.
> After bisecting, it turned out to be this patch causing the issue.

Funnily enough; the email you replied to didn't contain a patch.

> Test case:
> Load module and run perf for more than 4 events( we have 4 counters,
> event multiplexing takes place for more than 4 events), then unload
> module.
> With this sequence of testing, the system hangs(soft lockup) after 2
> or 3 iterations. Same test runs for hours on 5.2.
> 
> while [ 1 ]
> do
>         rmmod thunderx2_pmu
>         modprobe thunderx2_pmu
>         perf stat -a -e \
>         uncore_dmc_0/cnt_cycles/,\
>         uncore_dmc_0/data_transfers/,\
>         uncore_dmc_0/read_txns/,\
>         uncore_dmc_0/config=0xE/,\
>         uncore_dmc_0/write_txns/ sleep 1
>         sleep 2
> done

Can you reproduce without the module load+unload? I don't think people
routinely unload modules.



  reply	other threads:[~2019-08-23 11:59 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-01  8:27 [PATCH] perf cgroups: Don't rotate events for cgroups unnecessarily Ian Rogers
2019-06-13 16:12 ` Liang, Kan
2019-06-14 19:10   ` Stephane Eranian
2019-06-14 21:43     ` Liang, Kan
2019-06-20 23:08       ` Ian Rogers
2019-06-21  8:24 ` Peter Zijlstra
2019-06-21 18:01   ` Ian Rogers
2019-06-24  7:55     ` Peter Zijlstra
2019-06-27 21:47       ` Ian Rogers
2019-08-23 10:43         ` Ganapatrao Kulkarni
2019-08-23 11:59           ` Peter Zijlstra [this message]
2019-08-23 12:56             ` Ganapatrao Kulkarni
2019-08-23 13:03               ` Peter Zijlstra
2019-09-18  7:21                 ` Ganapatrao Kulkarni
2019-10-15  4:43                   ` Ganapatrao Kulkarni
2019-06-25  8:43 ` [tip:perf/core] perf/cgroups: " tip-bot for Ian Rogers

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