From: Yin Fengwei <fengwei.yin@intel.com>
To: Yosry Ahmed <yosryahmed@google.com>
Cc: kernel test robot <oliver.sang@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Shakeel Butt <shakeelb@google.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Muchun Song <songmuchun@bytedance.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>, <lkp@lists.01.org>,
<lkp@intel.com>, Ying <ying.huang@intel.com>,
<feng.tang@intel.com>, <zhengjun.xing@linux.intel.com>
Subject: Re: [memcg] a8c49af3be: hackbench.throughput -13.7% regression
Date: Wed, 27 Apr 2022 12:59:20 +0800 [thread overview]
Message-ID: <1971eb3a-d689-8b35-e500-8a60f41765db@intel.com> (raw)
In-Reply-To: <CAJD7tkaDWtgy3Ckhgo+vcbM7oYA8saPCVRvXLDKYHvRGYkKvoQ@mail.gmail.com>
Hi Yosry,
On 4/27/2022 12:34 PM, Yosry Ahmed wrote:
> I am not sure why this specific callsite causes regression, there are
> many callsites that modify stats similarly (whether through
> mod_memcg_state() directly or through other variants like
> mod_lruvec_state()). Maybe the kmem call path is exercised more
> heavily in this benchmark than other call paths that update stats.
perf data didn't show the function commented out either. No idea how
it impact the hackbench.
>
> The only seemingly expensive operation in the mod_memcg_state() path
> is the call to cgroup_rstat_updated() (through memcg_rstat_updated()).
> One idea off the top of my head is to batch calls to
> cgroup_rstat_updated(), similar to what 11192d9c124d ("memcg: flush
> stats only if updated") did on the flush side. I am interested to see
> what memcg maintainers think about this problem (and the proposed
> solution).
OK. Let's wait.
Regards
Yin, Fengwei
next prev parent reply other threads:[~2022-04-27 4:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-20 5:58 [memcg] a8c49af3be: hackbench.throughput -13.7% regression kernel test robot
2022-04-27 2:52 ` Yin Fengwei
2022-04-27 4:34 ` Yosry Ahmed
2022-04-27 4:59 ` Yin Fengwei [this message]
2022-04-27 5:08 ` Shakeel Butt
2022-04-27 5:02 ` Shakeel Butt
2022-04-27 5:03 ` Yin Fengwei
2022-04-28 5:12 ` Yin Fengwei
2022-04-28 13:16 ` Shakeel Butt
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