linux-kernel - Re: [RFC PATCH 24/24] sched/time: Introduce CLOCK_THREAD_DVFS

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: <20240802112953.GJ39708@noisy.programming.kicks-ass.net>
Date: Fri, 2 Aug 2024 13:29:53 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Juri Lelli <juri.lelli@...hat.com>
Cc: mingo@...hat.com, vincent.guittot@...aro.org, dietmar.eggemann@....com,
	rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
	vschneid@...hat.com, linux-kernel@...r.kernel.org,
	kprateek.nayak@....com, wuyun.abel@...edance.com,
	youssefesmat@...omium.org, tglx@...utronix.de, efault@....de
Subject: Re: [RFC PATCH 24/24] sched/time: Introduce CLOCK_THREAD_DVFS_ID

On Mon, Jul 29, 2024 at 09:53:17AM +0200, Juri Lelli wrote:
> Hi Peter,
> 
> On 27/07/24 12:27, Peter Zijlstra wrote:
> > In order to measure thread time in a DVFS world, introduce
> > CLOCK_THREAD_DVFS_ID -- a copy of CLOCK_THREAD_CPUTIME_ID that slows
> > down with both DVFS scaling and CPU capacity.
> > 
> > The clock does *NOT* support setting timers.
> > 
> > Useful for both SCHED_DEADLINE and the newly introduced
> > sched_attr::sched_runtime usage for SCHED_NORMAL.
> 
> Just so I'm sure I understand, this would be useful for estimating the
> runtime needs of a (also DEADLINE) task when DVFS is enabled, right?

Correct, DVFS or biggie-smalls CPUs with mixed capacities.