linux-kernel - Re: [PATCH RFC 3/8] sched/ext: Add a DL server for sched

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z9hUby9e1JYaE6iC@slm.duckdns.org>
Date: Mon, 17 Mar 2025 06:57:19 -1000
From: Tejun Heo <tj@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Joel Fernandes <joelagnelf@...dia.com>, linux-kernel@...r.kernel.org,
	Andrea Righi <arighi@...dia.com>, Ingo Molnar <mingo@...hat.com>,
	Juri Lelli <juri.lelli@...hat.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>,
	David Vernet <void@...ifault.com>,
	Changwoo Min <changwoo@...lia.com>,
	Luigi De Matteis <ldematteis123@...il.com>, paulmck@...nel.org,
	boqun.feng@...il.com
Subject: Re: [PATCH RFC 3/8] sched/ext: Add a DL server for sched_ext tasks

Hello,

On Mon, Mar 17, 2025 at 11:31:01AM +0100, Peter Zijlstra wrote:
> On Sat, Mar 15, 2025 at 07:15:27PM -0400, Joel Fernandes wrote:
> > If so, that will not handle the case where the system has both
> > FAIR and EXT tasks in the mix (EXT has a partial mode where certain tasks can be
> > made EXT with certain others left as FAIR) and FAIR runs 100% and starves EXT.
> 
> Well, you did not mention that issue, you only babbled about RT.
> 
> I did point out that issue with ext, and TJ said this mixed mode wasn't
> really meant to be used or somesuch.

It's true that most of the current use cases don't use mixed mode. That
said, some folks are interested in it and if we can prevent starvation from
fair saturating CPUs in mixed mode with a DL server, that'd be really nice.
Would it be possible to toggle the reservations depending on the ext's
operation mode?

Thanks.

-- 
tejun