linux-kernel - Re: [RFCv3 PATCH 33/48] sched: Energy-aware wake-up task placement

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]

Date:	Thu, 26 Mar 2015 11:41:50 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Juri Lelli <juri.lelli@....com>
Cc:	Morten Rasmussen <Morten.Rasmussen@....com>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
	Dietmar Eggemann <Dietmar.Eggemann@....com>,
	"yuyang.du@...el.com" <yuyang.du@...el.com>,
	"preeti@...ux.vnet.ibm.com" <preeti@...ux.vnet.ibm.com>,
	"mturquette@...aro.org" <mturquette@...aro.org>,
	"nico@...aro.org" <nico@...aro.org>,
	"rjw@...ysocki.net" <rjw@...ysocki.net>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFCv3 PATCH 33/48] sched: Energy-aware wake-up task placement

On Thu, Mar 26, 2015 at 10:21:24AM +0000, Juri Lelli wrote:
>  - what about other sched classes? I know that this is very premature,
>    but I can help but thinking that we'll need to do some sort of
>    aggregation of requests, and if we put triggers in very specialized
>    points we might lose some of the sched classes separation

So for deadline we can do P state selection (as you're well aware) based
on the requested utilization. Not sure what to do for fifo/rr though,
they lack much useful information (as always).

Now if we also look ahead to things like the ACPI CPPC stuff we'll see
that CFS and DL place different requirements on the hints. Where CFS
would like to hint a max perf (the hardware going slower due to the code
consisting of mostly stalls is always fine from a best effort energy
pov), the DL stuff would like to hint a min perf, seeing how it 'needs'
to provide a QoS.

So we either need to carry this information along in a 'generic' way
between the various classes or put the hinting in every class.

But yes, food for thought for sure.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/