linux-kernel - Re: [PATCH v1 0/4] Enable >0 order folio memory compaction

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <7ED1378A-AC39-48A2-8A2A-E06C7858DCE1@nvidia.com>
Date:   Tue, 21 Nov 2023 11:45:22 -0500
From:   Zi Yan <ziy@...dia.com>
To:     Ryan Roberts <ryan.roberts@....com>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        "\"Huang, Ying\"" <ying.huang@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "\"Matthew Wilcox (Oracle)\"" <willy@...radead.org>,
        David Hildenbrand <david@...hat.com>,
        "\"Yin, Fengwei\"" <fengwei.yin@...el.com>,
        Yu Zhao <yuzhao@...gle.com>, Vlastimil Babka <vbabka@...e.cz>,
        "\"Kirill A . Shutemov\"" <kirill.shutemov@...ux.intel.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Baolin Wang <baolin.wang@...ux.alibaba.com>,
        Kemeng Shi <shikemeng@...weicloud.com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Rohan Puri <rohan.puri15@...il.com>,
        Mcgrof Chamberlain <mcgrof@...nel.org>,
        Adam Manzanares <a.manzanares@...sung.com>,
        "\"Vishal Moola (Oracle)\"" <vishal.moola@...il.com>
Subject: Re: [PATCH v1 0/4] Enable >0 order folio memory compaction

On 21 Nov 2023, at 10:46, Ryan Roberts wrote:

>>
>> vm-scalability results
>> ===
>>
>> =========================================================================================
>> compiler/kconfig/rootfs/runtime/tbox_group/test/testcase:
>>   gcc-13/defconfig/debian/300s/qemu-vm/mmap-xread-seq-mt/vm-scalability
>>
>> commit:
>>   6.6.0-rc4-mm-everything-2023-10-21-02-40+
>>   6.6.0-rc4-split-folio-in-compaction+
>>   6.6.0-rc4-folio-migration-in-compaction+
>>   6.6.0-rc4-folio-migration-free-page-split+
>>   6.6.0-rc4-folio-migration-free-page-split-sort-src+
>>
>> 6.6.0-rc4-mm-eve 6.6.0-rc4-split-folio-in-co 6.6.0-rc4-folio-migration-i 6.6.0-rc4-folio-migration-f 6.6.0-rc4-folio-migration-f
>> ---------------- --------------------------- --------------------------- --------------------------- ---------------------------
>>          %stddev     %change         %stddev     %change         %stddev     %change         %stddev     %change         %stddev
>>              \          |                \          |                \          |                \          |                \
>>   12896955            +2.7%   13249322            -4.0%   12385175 ±  5%      +1.1%   13033951            -0.4%   12845698        vm-scalability.throughput
>
> Hi Zi,
>
> Are you able to add any commentary to these results as I'm struggling to
> interpret them; Is a positive or negative change better (are they times or
> rates?). What are the stddev values? The title suggests percent but the values
> are huge - I'm trying to understand what the error bars look like - are the
> swings real or noise?

The metric is vm-scalability.throughput, so the larger the better. Some %stddev
are not present since they are too small. For 6.6.0-rc4-folio-migration-in-compaction+,
%stddev is greater than %change, so the change might be noise.

Also, I talked to DavidH in last THP Cabal meeting about this. He suggested that
there are a lot of noise in vm-scalability like what I have here and I should
run more iterations and on bare metal. I am currently rerun them on a baremetal
and more iterations on the existing VM and report the results later. Please
note that the runs really take some time.

In addition, I will find other fragmentation-related benchmarks, so we can see
the impact on memory fragmentation.

--
Best Regards,
Yan, Zi

Download attachment "signature.asc" of type "application/pgp-signature" (855 bytes)