MIME-Version: 1.0
In-Reply-To: <566F7715.3020905@redhat.com>
References: <CAE4VaGAziCRGRXPPO6YtiHLXqeLUMcuYCh3mkmGpDjfW8GaetQ@mail.gmail.com>
	<1449903863.9638.8.camel@gmail.com>
	<CAE4VaGDvxXbTd2HKaQoh1Twj3NpZaJ0SkjH1qNZt704-Td5thw@mail.gmail.com>
	<1449931045.7411.8.camel@gmail.com>
	<CAE4VaGCgAvvQXDsv=Gn8B0JtTzCnXe0oP63HLQWSCyY_QNOB7g@mail.gmail.com>
	<566F7715.3020905@redhat.com>
Date: Tue, 15 Dec 2015 09:49:28 +0100
Message-ID: <CAE4VaGDsf8gbWdMJaUNbt7s6MrYX931982h=AvUxn9+OSKX0Zw@mail.gmail.com>
Subject: Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel
From: Jirka Hladky <jhladky@redhat.com>
To: Rik van Riel <riel@redhat.com>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>, linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1489
Lines: 40

Hi Rik,

I have reviewed the data and you are right. The trouble is that even
with 4.3 kernel there is 20% change that results will be bad. I have
repeated tests 100 times on 4.3 kernel over the night. In 20 cases I
see that runtime went up from 12 seconds to 28 seconds due to the
wrong NUMA placement. I will try to replay the bisect once again.

Jirka

On Tue, Dec 15, 2015 at 3:12 AM, Rik van Riel <riel@redhat.com> wrote:
> On 12/14/2015 06:52 PM, Jirka Hladky wrote:
>> Hi all,
>>
>> I have the results of bisecting:
>>
>> first bad commit: [973759c80db96ed4b4c5cb85ac7d48107f801371] Merge tag
>> 'v4.3-rc1' into sched/core, to refresh the branch
>>
>> Could you please have a look at this commit why it has caused the
>> performance regression when running 4 stream benchmarks in parallel on 4
>> NUMA node server?
>
> That is a merge commit. It contains no actual code changes.
>
>> Please let me know if you need additional data. git bisect log is bellow.
>
> It looks like "git bisect" may have led you astray.
>
> I am not sure what debugging tool to use to figure out which
> of the patches from some merged-in branch caused the issue,
> but hopefully one of the people reading this email know a trick.
>
> --
> All rights reversed
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/