From: "Huang\, Ying" <ying.huang@intel.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Minchan Kim <minchan@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, "Huang\,
Ying" <ying.huang@intel.com>, Rik van Riel <riel@redhat.com>,
Michal Hocko <mhocko@suse.com>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
"Vinayak Menon" <vinmenon@codeaurora.org>,
Mel Gorman <mgorman@suse.de>,
Andrew Morton <akpm@linux-foundation.org>, <lkp@01.org>
Subject: Re: [LKP] [lkp] [mm] 5c0a85fad9: unixbench.score -6.3% regression
Date: Thu, 16 Jun 2016 07:52:26 +0800 [thread overview]
Message-ID: <877fdqxb5x.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <20160614143417.GC3571@node.shutemov.name> (Kirill A. Shutemov's message of "Tue, 14 Jun 2016 17:34:17 +0300")
"Kirill A. Shutemov" <kirill@shutemov.name> writes:
> On Tue, Jun 14, 2016 at 05:57:28PM +0900, Minchan Kim wrote:
>> On Wed, Jun 08, 2016 at 11:58:11AM +0300, Kirill A. Shutemov wrote:
>> > On Wed, Jun 08, 2016 at 04:41:37PM +0800, Huang, Ying wrote:
>> > > "Huang, Ying" <ying.huang@intel.com> writes:
>> > >
>> > > > "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> writes:
>> > > >
>> > > >> On Mon, Jun 06, 2016 at 10:27:24AM +0800, kernel test robot wrote:
>> > > >>>
>> > > >>> FYI, we noticed a -6.3% regression of unixbench.score due to commit:
>> > > >>>
>> > > >>> commit 5c0a85fad949212b3e059692deecdeed74ae7ec7 ("mm: make faultaround produce old ptes")
>> > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> > > >>>
>> > > >>> in testcase: unixbench
>> > > >>> on test machine: lituya: 16 threads Haswell High-end Desktop (i7-5960X 3.0G) with 16G memory
>> > > >>> with following parameters: cpufreq_governor=performance/nr_task=1/test=shell8
>> > > >>>
>> > > >>>
>> > > >>> Details are as below:
>> > > >>> -------------------------------------------------------------------------------------------------->
>> > > >>>
>> > > >>>
>> > > >>> =========================================================================================
>> > > >>> compiler/cpufreq_governor/kconfig/nr_task/rootfs/tbox_group/test/testcase:
>> > > >>> gcc-4.9/performance/x86_64-rhel/1/debian-x86_64-2015-02-07.cgz/lituya/shell8/unixbench
>> > > >>>
>> > > >>> commit:
>> > > >>> 4b50bcc7eda4d3cc9e3f2a0aa60e590fedf728c5
>> > > >>> 5c0a85fad949212b3e059692deecdeed74ae7ec7
>> > > >>>
>> > > >>> 4b50bcc7eda4d3cc 5c0a85fad949212b3e059692de
>> > > >>> ---------------- --------------------------
>> > > >>> fail:runs %reproduction fail:runs
>> > > >>> | | |
>> > > >>> 3:4 -75% :4 kmsg.DHCP/BOOTP:Reply_not_for_us,op[#]xid[#]
>> > > >>> %stddev %change %stddev
>> > > >>> \ | \
>> > > >>> 14321 . 0% -6.3% 13425 . 0% unixbench.score
>> > > >>> 1996897 . 0% -6.1% 1874635 . 0% unixbench.time.involuntary_context_switches
>> > > >>> 1.721e+08 . 0% -6.2% 1.613e+08 . 0% unixbench.time.minor_page_faults
>> > > >>> 758.65 . 0% -3.0% 735.86 . 0% unixbench.time.system_time
>> > > >>> 387.66 . 0% +5.4% 408.49 . 0% unixbench.time.user_time
>> > > >>> 5950278 . 0% -6.2% 5583456 . 0% unixbench.time.voluntary_context_switches
>> > > >>
>> > > >> That's weird.
>> > > >>
>> > > >> I don't understand why the change would reduce number or minor faults.
>> > > >> It should stay the same on x86-64. Rise of user_time is puzzling too.
>> > > >
>> > > > unixbench runs in fixed time mode. That is, the total time to run
>> > > > unixbench is fixed, but the work done varies. So the minor_page_faults
>> > > > change may reflect only the work done.
>> > > >
>> > > >> Hm. Is reproducible? Across reboot?
>> > > >
>> > >
>> > > And FYI, there is no swap setup for test, all root file system including
>> > > benchmark files are in tmpfs, so no real page reclaim will be
>> > > triggered. But it appears that active file cache reduced after the
>> > > commit.
>> > >
>> > > 111331 . 1% -13.3% 96503 . 0% meminfo.Active
>> > > 27603 . 1% -43.9% 15486 . 0% meminfo.Active(file)
>> > >
>> > > I think this is the expected behavior of the commit?
>> >
>> > Yes, it's expected.
>> >
>> > After the change faularound would produce old pte. It means there's more
>> > chance for these pages to be on inactive lru, unless somebody actually
>> > touch them and flip accessed bit.
>>
>> Hmm, tmpfs pages should be in anonymous LRU list and VM shouldn't scan
>> anonymous LRU list on swapless system so I really wonder why active file
>> LRU is shrunk.
>
> Hm. Good point. I don't why we have anything on file lru if there's no
> filesystems except tmpfs.
>
> Ying, how do you get stuff to the tmpfs?
We put root file system and benchmark into a set of compressed cpio
archive, then concatenate them into one initrd, and finally kernel use
that initrd as initramfs.
Best Regards,
Huang, Ying
next prev parent reply other threads:[~2016-06-15 23:52 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 2:27 [lkp] [mm] 5c0a85fad9: unixbench.score -6.3% regression kernel test robot
2016-06-06 9:51 ` Kirill A. Shutemov
2016-06-08 7:21 ` [LKP] " Huang, Ying
2016-06-08 8:41 ` Huang, Ying
2016-06-08 8:58 ` Kirill A. Shutemov
2016-06-12 0:49 ` Huang, Ying
2016-06-12 1:02 ` Linus Torvalds
2016-06-13 9:02 ` Huang, Ying
2016-06-14 13:38 ` Minchan Kim
2016-06-15 23:42 ` Huang, Ying
2016-06-13 12:52 ` Kirill A. Shutemov
2016-06-14 6:11 ` Linus Torvalds
2016-06-14 8:26 ` Kirill A. Shutemov
2016-06-14 16:07 ` Rik van Riel
2016-06-14 14:03 ` Christian Borntraeger
2016-06-14 8:57 ` Minchan Kim
2016-06-14 14:34 ` Kirill A. Shutemov
2016-06-15 23:52 ` Huang, Ying [this message]
2016-06-16 0:13 ` Minchan Kim
2016-06-16 22:27 ` Huang, Ying
2016-06-17 5:41 ` Minchan Kim
2016-06-17 19:26 ` Huang, Ying
2016-06-20 0:06 ` Minchan Kim
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=877fdqxb5x.fsf@yhuang-dev.intel.com \
--to=ying.huang@intel.com \
--cc=akpm@linux-foundation.org \
--cc=kirill.shutemov@linux.intel.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@01.org \
--cc=mgorman@suse.de \
--cc=mhocko@kernel.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=riel@redhat.com \
--cc=torvalds@linux-foundation.org \
--cc=vinmenon@codeaurora.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).