Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <cover.1559129225.git.vpillai@digitalocean.com>
In-Reply-To: <cover.1559129225.git.vpillai@digitalocean.com>
From:   Aubrey Li <aubrey.intel@gmail.com>
Date:   Thu, 30 May 2019 22:04:39 +0800
Message-ID: <CAERHkruDE-7R5K=2yRqCJRCpV87HkHzDYbQA2WQkruVYpG7t7Q@mail.gmail.com>
Subject: Re: [RFC PATCH v3 00/16] Core scheduling v3
To:     Vineeth Remanan Pillai <vpillai@digitalocean.com>
Cc:     Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Julien Desfossez <jdesfossez@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>,
        Subhra Mazumdar <subhra.mazumdar@oracle.com>,
        =?UTF-8?B?RnLDqWTDqXJpYyBXZWlzYmVja2Vy?= <fweisbec@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Greg Kerr <kerrnel@google.com>, Phil Auld <pauld@redhat.com>,
        Aaron Lu <aaron.lwe@gmail.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>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, May 30, 2019 at 4:36 AM Vineeth Remanan Pillai
<vpillai@digitalocean.com> wrote:
>
> Third iteration of the Core-Scheduling feature.
>
> This version fixes mostly correctness related issues in v2 and
> addresses performance issues. Also, addressed some crashes related
> to cgroups and cpu hotplugging.
>
> We have tested and verified that incompatible processes are not
> selected during schedule. In terms of performance, the impact
> depends on the workload:
> - on CPU intensive applications that use all the logical CPUs with
>   SMT enabled, enabling core scheduling performs better than nosmt.
> - on mixed workloads with considerable io compared to cpu usage,
>   nosmt seems to perform better than core scheduling.

My testing scripts can not be completed on this version. I figured out the
number of cpu utilization report entry didn't reach my minimal requirement.
Then I wrote a simple script to verify.
====================
$ cat test.sh
#!/bin/sh

for i in `seq 1 10`
do
    echo `date`, $i
    sleep 1
done
====================

Normally it works as below:

Thu May 30 14:13:40 CST 2019, 1
Thu May 30 14:13:41 CST 2019, 2
Thu May 30 14:13:42 CST 2019, 3
Thu May 30 14:13:43 CST 2019, 4
Thu May 30 14:13:44 CST 2019, 5
Thu May 30 14:13:45 CST 2019, 6
Thu May 30 14:13:46 CST 2019, 7
Thu May 30 14:13:47 CST 2019, 8
Thu May 30 14:13:48 CST 2019, 9
Thu May 30 14:13:49 CST 2019, 10

When the system was running 32 sysbench threads and
32 gemmbench threads, it worked as below(the system
has ~38% idle time)
Thu May 30 14:14:20 CST 2019, 1
Thu May 30 14:14:21 CST 2019, 2
Thu May 30 14:14:22 CST 2019, 3
Thu May 30 14:14:24 CST 2019, 4 <=======x=
Thu May 30 14:14:25 CST 2019, 5
Thu May 30 14:14:26 CST 2019, 6
Thu May 30 14:14:28 CST 2019, 7 <=======x=
Thu May 30 14:14:29 CST 2019, 8
Thu May 30 14:14:31 CST 2019, 9 <=======x=
Thu May 30 14:14:34 CST 2019, 10 <=======x=

And it got worse when the system was running 64/64 case,
the system still had ~3% idle time
Thu May 30 14:26:40 CST 2019, 1
Thu May 30 14:26:46 CST 2019, 2
Thu May 30 14:26:53 CST 2019, 3
Thu May 30 14:27:01 CST 2019, 4
Thu May 30 14:27:03 CST 2019, 5
Thu May 30 14:27:11 CST 2019, 6
Thu May 30 14:27:31 CST 2019, 7
Thu May 30 14:27:32 CST 2019, 8
Thu May 30 14:27:41 CST 2019, 9
Thu May 30 14:27:56 CST 2019, 10

Any thoughts?

Thanks,
-Aubrey