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From: 王贇 <yun.wang@linux.alibaba.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Iurii Zaikin <yzaikin@google.com>,
	Michal Koutn? <mkoutny@suse.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org,
	"Paul E. McKenney" <paulmck@linux.ibm.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH RESEND v8 1/2] sched/numa: introduce per-cgroup NUMA locality info
Date: Mon, 24 Feb 2020 11:09:06 +0800	[thread overview]
Message-ID: <3bd3f4d0-2504-a48c-adea-a28227a81d7a@linux.alibaba.com> (raw)
In-Reply-To: <20200221152824.GH18400@hirez.programming.kicks-ass.net>



On 2020/2/21 下午11:28, Peter Zijlstra wrote:
> On Mon, Feb 17, 2020 at 09:23:52PM +0800, 王贇 wrote:
>> FYI, by monitoring locality, we found that the kvm vcpu thread is not
>> covered by NUMA Balancing, whatever how many maximum period passed, the
>> counters are not increasing, or very slowly, although inside guest we are
>> copying memory.
>>
>> Later we found such task rarely exit to user space to trigger task
>> work callbacks, and NUMA Balancing scan depends on that, which help us
>> realize the importance to enable NUMA Balancing inside guest, with the
>> correct NUMA topo, a big performance risk I'll say :-P
> 
> That's a bug in KVM, see:
> 
>   https://lkml.kernel.org/r/20190801143657.785902257@linutronix.de
>   https://lkml.kernel.org/r/20190801143657.887648487@linutronix.de
> 
> ISTR there being newer versions of that patch-set, but I can't seem to
> find them in a hurry.

Aha, that's exactly the problem we saw, will check~

Regards,
Michael Wang

> 

  reply	other threads:[~2020-02-24  3:09 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-07  3:34 [PATCH RESEND v8 0/2] sched/numa: introduce numa locality 王贇
2020-02-07  3:35 ` [PATCH RESEND v8 1/2] sched/numa: introduce per-cgroup NUMA locality info 王贇
2020-02-07  3:37   ` 王贇
2020-02-13  2:35     ` 王贇
2020-02-14 15:10   ` Peter Zijlstra
2020-02-17 11:58     ` Mel Gorman
2020-02-17 13:23       ` 王贇
2020-02-17 14:16         ` Mel Gorman
2020-02-18  1:39           ` 王贇
2020-02-21 14:20             ` Mel Gorman
2020-02-21 15:47               ` Peter Zijlstra
2020-02-24  3:13                 ` 王贇
2020-02-24  3:05               ` 王贇
2020-02-21 15:28         ` Peter Zijlstra
2020-02-24  3:09           ` 王贇 [this message]
2020-02-07  3:35 ` [PATCH RESEND v8 2/2] sched/numa: documentation for per-cgroup numa 王贇

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