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From: "Huang\, Ying" <ying.huang@intel.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: "Huang\, Ying" <ying.huang@intel.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Andi Kleen <ak@linux.intel.com>, Tim Chen <tim.c.chen@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>, LKP <lkp@01.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>
Subject: Re: [LKP] [lkp-developer] [sched/fair] 4e5160766f: +149% ftq.noise.50% regression
References: <87zik1ya5g.fsf@yhuang-dev.intel.com>
        <CAKfTPtA_Wti+Nu5f3wajqJTg35jBwZAn=mD=DUK91Y9GSqH6AQ@mail.gmail.com>
        <878trk8urx.fsf@yhuang-dev.intel.com>
        <20161222151215.GA23448@linaro.org>
        <87r34swjqg.fsf@yhuang-dev.intel.com>
        <CAKfTPtARomXaQsk92aVdeGqwimhQPYzi6suMAiyT-6Zwjso1Dw@mail.gmail.com>
        <cfdd7004-efe0-1b90-2359-a08092c1fbe1@arm.com>
        <20170103113759.GA30094@linaro.org>
        <87a8b7o72c.fsf@yhuang-dev.intel.com>
        <CAKfTPtBLZ4Fm5cPiFAdF3N16LaqE+SsFkbi3USWYL0iSK9sDdA@mail.gmail.com>
        <87d1ecs1ud.fsf@yhuang-dev.intel.com>
        <CAKfTPtBN+NmOXREQK6v-_dfrcDNux-BUG0A7xk3oOj-s7t37Bg@mail.gmail.com>
Date: Tue, 28 Feb 2017 08:33:27 +0800
In-Reply-To: <CAKfTPtBN+NmOXREQK6v-_dfrcDNux-BUG0A7xk3oOj-s7t37Bg@mail.gmail.com>
        (Vincent Guittot's message of "Mon, 27 Feb 2017 10:44:02 +0100")
Message-ID: <87tw7ff92g.fsf@yhuang-dev.intel.com>
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Vincent Guittot <vincent.guittot@linaro.org> writes:

> Hi Ying,
>
> On 21 February 2017 at 03:40, Huang, Ying <ying.huang@intel.com> wrote:
>> Hi, Vincent,
>>
>> Vincent Guittot <vincent.guittot@linaro.org> writes:
>>
>
> [snip]
>
>>>>
>>>> Here is the test result,
>>>>
>>>> =========================================================================================
>>>> compiler/cpufreq_governor/freq/kconfig/nr_task/rootfs/samples/tbox_group/test/testcase:
>>>>   gcc-6/powersave/20/x86_64-rhel-7.2/100%/debian-x86_64-2016-08-31.cgz/6000ss/lkp-hsw-d01/cache/ftq
>>>>
>>>> commit:
>>>>   4e5160766fcc9f41bbd38bac11f92dce993644aa: first bad commit
>>>>   09a43ace1f986b003c118fdf6ddf1fd685692d49: parent of first bad commit
>>>>   b524060933c546fd2410c5a09360ba23a0fef846: with fix patch above
>>>>
>>>> 4e5160766fcc9f41 09a43ace1f986b003c118fdf6d b524060933c546fd2410c5a093
>>>> ---------------- -------------------------- --------------------------
>>>>          %stddev     %change         %stddev     %change         %stddev
>>>>              \          |                \          |                \
>>>>       3463 ± 10%     -61.4%       1335 ± 17%      -3.0%       3359 ±  2%  ftq.noise.50%
>>>>       1116 ± 23%     -73.7%     293.90 ± 30%     -23.8%     850.69 ± 17%  ftq.noise.75%
>>>
>>> To be honest, I was expecting at least the same level of improvement
>>> as the previous patch if not better but i was not expecting worse
>>> results
>>
>> What's your next plan for this regression?  At least your previous patch
>> could recover part of it.
>
> I haven't been able to find better fix than the previous patch so i'm
> going to send a clean version with proper commit message

Great to know this.  Could you keep me posted?

Best Regards,
Huang, Ying

> Regards,
> Vincent
>
>>
>> Best Regards,
>> Huang, Ying