Message-ID: <5b567c5aecabf0a89d92593d99a73bef41bd65da.camel@gmx.de>
Subject: Re: [PATCH 10/10] sched/fair: Implement an EEVDF like policy
From:   Mike Galbraith <efault@gmx.de>
To:     Peter Zijlstra <peterz@infradead.org>, mingo@kernel.org,
        vincent.guittot@linaro.org
Cc:     linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        mgorman@suse.de, bristot@redhat.com, corbet@lwn.net,
        qyousef@layalina.io, chris.hyser@oracle.com,
        patrick.bellasi@matbug.net, pjt@google.com, pavel@ucw.cz,
        qperret@google.com, tim.c.chen@linux.intel.com, joshdon@google.com,
        timj@gnu.org, kprateek.nayak@amd.com, yu.c.chen@intel.com,
        youssefesmat@chromium.org, joel@joelfernandes.org
Date:   Thu, 09 Mar 2023 05:23:33 +0100
In-Reply-To: <9fd2c37a05713c206dcbd5866f67ce779f315e9e.camel@gmx.de>
References: <20230306132521.968182689@infradead.org>
         <20230306141502.810909205@infradead.org>
         <bfbfbf041854e2cd1a8ed14e64081062e5d632d3.camel@gmx.de>
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Precedence: bulk

On Wed, 2023-03-08 at 14:36 +0100, Mike Galbraith wrote:
>
> Remember this little bugger, allegedly distilled from a real
> application control thread starvation issue?
>
> 6.3.0.g8ca09d5-master
> homer:/root # time taskset -c 3 starve=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0
> expecting to receive 10000000 signals
>
> real=C2=A0=C2=A0=C2=A0 0m24.424s
> user=C2=A0=C2=A0=C2=A0 0m4.468s
> sys=C2=A0=C2=A0=C2=A0=C2=A0 0m18.957s
>
> 6.3.0.g8ca09d5-eevdf
> homer:/root # time taskset -c 3 starve
> expecting to receive 10000000 signals
> zzzzzz
> ^C

Ok, seems there must be a math booboo lurking.

virgin source, 100% hog vs tbench buddy pair, all pinned.

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ P COM=
MAND
 5060 root      20   0    4420    680    680 R 96.01 0.004   0:41.40 3 cpu=
hog
 5058 root      20   0   25500   1920   1792 S 2.326 0.012   0:01.05 3 tbe=
nch
 5059 root      20   0    8796    896    768 R 1.661 0.006   0:00.78 3 tbe=
nch_srv

echo NO_PRESERVE_LAG > features

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ P COM=
MAND
 5060 root      20   0    4420    680    680 R 99.33 0.004   1:28.24 3 cpu=
hog
 5058 root      20   0   25500   1920   1792 R 0.333 0.012   0:01.75 3 tbe=
nch
 5059 root      20   0    8796    896    768 S 0.333 0.006   0:01.30 3 tbe=
nch_srv