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Message-ID: <747627a1414f1f33d0c237f555494149d6937800.camel@gmx.de>
Subject: Re: [RFC][PATCH 08/10] sched/fair: Implement delayed dequeue
From: Mike Galbraith <efault@gmx.de>
To: K Prateek Nayak <kprateek.nayak@amd.com>, Peter Zijlstra
 <peterz@infradead.org>, mingo@redhat.com, juri.lelli@redhat.com, 
 vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, 
 bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
 vschneid@redhat.com,  linux-kernel@vger.kernel.org
Cc: wuyun.abel@bytedance.com, tglx@linutronix.de, Chen Yu
 <yu.c.chen@intel.com>,  Oliver Sang <oliver.sang@intel.com>
Date: Tue, 16 Apr 2024 07:36:28 +0200
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On Tue, 2024-04-16 at 08:48 +0530, K Prateek Nayak wrote:
>
> Wondering if you are running into the issue where pick_eevdf() returns
> NULL despite there being runnable CFS task on the runqueue. Can you try
> running with the following patch from Chenyu -
> https://lore.kernel.org/lkml/20240226082349.302363-1-yu.c.chen@intel.com=
/

I hadn't tried it in master branch, but had in my 6.1-eevdf tree which
contains the previous delay dequeue version, because I found that it
too would explode, which surprised me having run it quite a bit woe
free. Patch helped 6.1-eevdf not at all.  I just tried it in master to
be sure, and while the death throes were not identical, this one began
with SCHED_WARN_ON() in put_prev_entity(), box still went belly up.

BTW/FWIW, turning on AUTOGROUP seemingly rendered box immune (unless
booted with noautogroup 'course), and that immunity even held when I
launched all players in the same cgroup (hmm).

	-Mike