From: Andrew Morton <akpm@linux-foundation.org>
To: lkp@lists.01.org
Subject: Re: [PATCH v2 2/3] mm: page_counter: rearrange struct page_counter fields
Date: Wed, 24 Aug 2022 17:33:30 -0700 [thread overview]
Message-ID: <20220824173330.2a15bcda24d2c3c248bc43c7@linux-foundation.org> (raw)
In-Reply-To: <20220825000506.239406-3-shakeelb@google.com>
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On Thu, 25 Aug 2022 00:05:05 +0000 Shakeel Butt <shakeelb@google.com> wrote:
> With memcg v2 enabled, memcg->memory.usage is a very hot member for
> the workloads doing memcg charging on multiple CPUs concurrently.
> Particularly the network intensive workloads. In addition, there is a
> false cache sharing between memory.usage and memory.high on the charge
> path. This patch moves the usage into a separate cacheline and move all
> the read most fields into separate cacheline.
>
> To evaluate the impact of this optimization, on a 72 CPUs machine, we
> ran the following workload in a three level of cgroup hierarchy.
>
> $ netserver -6
> # 36 instances of netperf with following params
> $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K
>
> Results (average throughput of netperf):
> Without (6.0-rc1) 10482.7 Mbps
> With patch 12413.7 Mbps (18.4% improvement)
>
> With the patch, the throughput improved by 18.4%.
>
> One side-effect of this patch is the increase in the size of struct
> mem_cgroup. For example with this patch on 64 bit build, the size of
> struct mem_cgroup increased from 4032 bytes to 4416 bytes. However for
> the performance improvement, this additional size is worth it. In
> addition there are opportunities to reduce the size of struct
> mem_cgroup like deprecation of kmem and tcpmem page counters and
> better packing.
Did you evaluate the effects of using a per-cpu counter of some form?
next prev parent reply other threads:[~2022-08-25 0:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 0:05 [PATCH v2 0/3] memcg: optimize charge codepath Shakeel Butt
2022-08-25 0:05 ` [PATCH v2 1/3] mm: page_counter: remove unneeded atomic ops for low/min Shakeel Butt
2022-08-25 6:43 ` Michal Hocko
2022-08-25 0:05 ` [PATCH v2 2/3] mm: page_counter: rearrange struct page_counter fields Shakeel Butt
2022-08-25 0:33 ` Andrew Morton [this message]
2022-08-25 4:41 ` Shakeel Butt
2022-08-25 5:21 ` Andrew Morton
2022-08-25 15:24 ` Shakeel Butt
2022-08-25 6:47 ` Michal Hocko
2022-08-25 15:25 ` Shakeel Butt
2022-08-25 0:05 ` [PATCH v2 3/3] memcg: increase MEMCG_CHARGE_BATCH to 64 Shakeel Butt
2022-08-25 6:49 ` Michal Hocko
2022-08-25 8:30 ` Muchun Song
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