From: "Huang, Ying" <ying.huang@intel.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
Arjan Van De Ven <arjan@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
David Hildenbrand <david@redhat.com>,
Johannes Weiner <jweiner@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Michal Hocko <mhocko@suse.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Matthew Wilcox <willy@infradead.org>,
"Christoph Lameter" <cl@linux.com>
Subject: Re: [PATCH 03/10] mm, pcp: reduce lock contention for draining high-order pages
Date: Thu, 12 Oct 2023 20:11:19 +0800 [thread overview]
Message-ID: <87cyxkf3bs.fsf@yhuang6-desk2.ccr.corp.intel.com> (raw)
In-Reply-To: <20231011124900.sp22hoxoitrslbia@techsingularity.net> (Mel Gorman's message of "Wed, 11 Oct 2023 13:49:00 +0100")
Mel Gorman <mgorman@techsingularity.net> writes:
> On Wed, Sep 20, 2023 at 02:18:49PM +0800, Huang Ying wrote:
>> In commit f26b3fa04611 ("mm/page_alloc: limit number of high-order
>> pages on PCP during bulk free"), the PCP (Per-CPU Pageset) will be
>> drained when PCP is mostly used for high-order pages freeing to
>> improve the cache-hot pages reusing between page allocating and
>> freeing CPUs.
>>
>> On system with small per-CPU data cache, pages shouldn't be cached
>> before draining to guarantee cache-hot. But on a system with large
>> per-CPU data cache, more pages can be cached before draining to reduce
>> zone lock contention.
>>
>> So, in this patch, instead of draining without any caching, "batch"
>> pages will be cached in PCP before draining if the per-CPU data cache
>> size is more than "4 * batch".
>>
>> On a 2-socket Intel server with 128 logical CPU, with the patch, the
>> network bandwidth of the UNIX (AF_UNIX) test case of lmbench test
>> suite with 16-pair processes increase 72.2%. The cycles% of the
>> spinlock contention (mostly for zone lock) decreases from 45.8% to
>> 21.2%. The number of PCP draining for high order pages
>> freeing (free_high) decreases 89.8%. The cache miss rate keeps 0.3%.
>>
>> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
>
> Acked-by: Mel Gorman <mgorman@techsingularity.net>
>
> However, the flag should also have been documented to make it clear that
> it preserves some pages on the PCP if the cache is large enough.
Sure. Will do this.
> Similar
> to the previous patch, it would have been easier to reason about in the
> general case if the decision had only been based on the LLC without
> having to worry if any intermediate layer has a meaningful impact that
> varies across CPU implementations.
Sure. Will do this.
--
Best Regards,
Huang, Ying
next prev parent reply other threads:[~2023-10-12 12:13 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-20 6:18 [PATCH 00/10] mm: PCP high auto-tuning Huang Ying
2023-09-20 6:18 ` [PATCH 01/10] mm, pcp: avoid to drain PCP when process exit Huang Ying
2023-10-11 12:46 ` Mel Gorman
2023-10-11 17:16 ` Andrew Morton
2023-10-12 13:09 ` Mel Gorman
2023-10-12 13:35 ` Huang, Ying
2023-10-12 12:21 ` Huang, Ying
2023-09-20 6:18 ` [PATCH 02/10] cacheinfo: calculate per-CPU data cache size Huang Ying
2023-09-20 9:24 ` Sudeep Holla
2023-09-22 7:56 ` Huang, Ying
2023-10-11 12:20 ` Mel Gorman
2023-10-12 12:08 ` Huang, Ying
2023-10-12 12:52 ` Mel Gorman
2023-10-12 13:12 ` Huang, Ying
2023-10-12 15:22 ` Mel Gorman
2023-10-13 3:06 ` Huang, Ying
2023-10-16 15:43 ` Mel Gorman
2023-09-20 6:18 ` [PATCH 03/10] mm, pcp: reduce lock contention for draining high-order pages Huang Ying
2023-10-11 12:49 ` Mel Gorman
2023-10-12 12:11 ` Huang, Ying [this message]
2023-09-20 6:18 ` [PATCH 04/10] mm: restrict the pcp batch scale factor to avoid too long latency Huang Ying
2023-10-11 12:52 ` Mel Gorman
2023-10-12 12:15 ` Huang, Ying
2023-09-20 6:18 ` [PATCH 05/10] mm, page_alloc: scale the number of pages that are batch allocated Huang Ying
2023-10-11 12:54 ` Mel Gorman
2023-09-20 6:18 ` [PATCH 06/10] mm: add framework for PCP high auto-tuning Huang Ying
2023-09-20 6:18 ` [PATCH 07/10] mm: tune PCP high automatically Huang Ying
2023-09-20 6:18 ` [PATCH 08/10] mm, pcp: decrease PCP high if free pages < high watermark Huang Ying
2023-10-11 13:08 ` Mel Gorman
2023-10-12 12:19 ` Huang, Ying
2023-09-20 6:18 ` [PATCH 09/10] mm, pcp: avoid to reduce PCP high unnecessarily Huang Ying
2023-10-11 14:09 ` Mel Gorman
2023-10-12 7:48 ` Huang, Ying
2023-10-12 12:49 ` Mel Gorman
2023-10-12 13:19 ` Huang, Ying
2023-09-20 6:18 ` [PATCH 10/10] mm, pcp: reduce detecting time of consecutive high order page freeing Huang Ying
2023-09-20 16:41 ` [PATCH 00/10] mm: PCP high auto-tuning Andrew Morton
2023-09-21 13:32 ` Huang, Ying
2023-09-21 15:46 ` Andrew Morton
2023-09-22 0:33 ` Huang, Ying
2023-10-11 13:05 ` Mel Gorman
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=87cyxkf3bs.fsf@yhuang6-desk2.ccr.corp.intel.com \
--to=ying.huang@intel.com \
--cc=akpm@linux-foundation.org \
--cc=arjan@linux.intel.com \
--cc=cl@linux.com \
--cc=dave.hansen@linux.intel.com \
--cc=david@redhat.com \
--cc=jweiner@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@suse.com \
--cc=pasha.tatashin@soleen.com \
--cc=vbabka@suse.cz \
--cc=willy@infradead.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