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From:   Shakeel Butt <shakeelb@google.com>
Date:   Sun, 25 Feb 2018 14:03:03 -0800
Message-ID: <CALvZod7=kgWDMPbrDUGXznoJgv47fq-PUa97onVhS8x73TR+6g@mail.gmail.com>
Subject: Re: [lkp-robot] [mm, mlock, vmscan] 9c4e6b1a70: stress-ng.hdd.ops_per_sec
 -7.9% regression
To:     kernel test robot <xiaolong.ye@intel.com>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        Huang Ying <ying.huang@intel.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Michal Hocko <mhocko@kernel.org>,
        Greg Thelen <gthelen@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Balbir Singh <bsingharora@gmail.com>,
        Minchan Kim <minchan@kernel.org>, Shaohua Li <shli@fb.com>,
        Jan Kara <jack@suse.cz>, Nicholas Piggin <npiggin@gmail.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Mel Gorman <mgorman@suse.de>, Hugh Dickins <hughd@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, lkp@01.org
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On Sun, Feb 25, 2018 at 6:44 AM, kernel test robot
<xiaolong.ye@intel.com> wrote:
>
> Greeting,
>
> FYI, we noticed a -7.9% regression of stress-ng.hdd.ops_per_sec due to commit:
>
>
> commit: 9c4e6b1a7027f102990c0395296015a812525f4d ("mm, mlock, vmscan: no more skipping pagevecs")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
> in testcase: stress-ng
> on test machine: 88 threads Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz with 128G memory
> with following parameters:
>

Hi Xiaolong,

Is there a way I can get the output of "perf record -a -g" running in
parallel to the actual test on this machine. As I have mentioned
before I am not able to reproduce this issue. However I am trying to
repro on a VM with 4 vcpus and 4 GiB memory and I don't see any
difference. I am suspecting that it may repro on a larger machine but
I don't have access to one.

thanks,
Shakeel