From: Shakeel Butt <shakeelb@google.com>
To: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Roman Gushchin <guro@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Cgroups <cgroups@vger.kernel.org>, Linux MM <linux-mm@kvack.org>
Subject: Re: memcg: performance degradation since v5.9
Date: Fri, 9 Apr 2021 09:50:45 -0700 [thread overview]
Message-ID: <CALvZod4uRU==p7Z0eP_xO49iA3ShFDHKzyWZbd7RdMso5PHsfA@mail.gmail.com> (raw)
In-Reply-To: <20210409163539.5374pde3u6gkbg4a@gabell>
On Fri, Apr 9, 2021 at 9:35 AM Masayoshi Mizuma <msys.mizuma@gmail.com> wrote:
>
[...]
> > Can you please explain how to read these numbers? Or at least put a %
> > regression.
>
> Let me summarize them here.
> The total duration ('total' column above) of each system call is as follows
> if v5.8 is assumed as 100%:
>
> - sendto:
> - v5.8 100%
> - v5.9 128%
> - v5.12-rc6 116%
>
> - revfrom:
> - v5.8 100%
> - v5.9 114%
> - v5.12-rc6 108%
>
Thanks, that is helpful. Most probably the improvement of 5.12 from
5.9 is due to 3de7d4f25a7438f ("mm: memcg/slab: optimize objcg stock
draining").
[...]
> >
> > One idea would be to increase MEMCG_CHARGE_BATCH.
>
> Thank you for the idea! It's hard-corded as 32 now, so I'm wondering it may be
> a good idea to make MEMCG_CHARGE_BATCH tunable from a kernel parameter or something.
>
Can you rerun the benchmark with MEMCG_CHARGE_BATCH equal 64UL?
I think with memcg stats moving to rstat, the stat accuracy is not an
issue if we increase MEMCG_CHARGE_BATCH to 64UL. Not sure if we want
this to be tuneable but most probably we do want this to be sync'ed
with SWAP_CLUSTER_MAX.
next prev parent reply other threads:[~2021-04-09 16:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 19:39 memcg: performance degradation since v5.9 Masayoshi Mizuma
2021-04-08 20:53 ` Roman Gushchin
2021-04-08 21:08 ` Shakeel Butt
2021-04-09 16:35 ` Masayoshi Mizuma
2021-04-09 16:50 ` Shakeel Butt [this message]
2021-04-12 15:22 ` Masayoshi Mizuma
2021-04-09 16:05 ` Masayoshi Mizuma
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