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Date:   Fri, 26 Jul 2019 11:21:01 -0400
From:   Julien Desfossez <jdesfossez@digitalocean.com>
To:     Aaron Lu <aaron.lu@linux.alibaba.com>
Cc:     Aubrey Li <aubrey.intel@gmail.com>,
        Subhra Mazumdar <subhra.mazumdar@oracle.com>,
        Vineeth Remanan Pillai <vpillai@digitalocean.com>,
        Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Paul Turner <pjt@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Greg Kerr <kerrnel@google.com>, Phil Auld <pauld@redhat.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC PATCH v3 00/16] Core scheduling v3
Message-ID: <20190726152101.GA27884@sinkpad>
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On 25-Jul-2019 10:30:03 PM, Aaron Lu wrote:
> 
> I tried a different approach based on vruntime with 3 patches following.
[...]

We have experimented with this new patchset and indeed the fairness is
now much better. Interactive tasks with v3 were complete starving when
there were cpu-intensive tasks running, now they can run consistently.
With my initial test of TPC-C running in large VMs with a lot of
background noise VMs, the results are pretty similar to v3, I will run
more thorough tests and report the results back here.

Instead of the 3/3 hack patch, we were already working on a different
approach to solve the same problem. What we have done so far is create a
very low priority per-cpu coresched_idle kernel thread that we use
instead of idle when we can't co-schedule tasks. This gives us more
control and accounting. It still needs some work, but the initial
results are encouraging, I will post more when we have something that
works well.

Thanks,

Julien