linux-kernel - Re: [RFCv3 PATCH 30/48] sched: Calculate energy consumption of 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]

Date:	Tue, 24 Mar 2015 17:39:55 +0000
From:	Morten Rasmussen <morten.rasmussen@....com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Dietmar Eggemann <Dietmar.Eggemann@....com>,
	Sai Gurrappadi <sgurrappadi@...dia.com>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
	"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>,
	Juri Lelli <Juri.Lelli@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Peter Boonstoppel <pboonstoppel@...dia.com>
Subject: Re: [RFCv3 PATCH 30/48] sched: Calculate energy consumption of
 sched_group

On Tue, Mar 24, 2015 at 04:10:37PM +0000, Peter Zijlstra wrote:
> On Tue, Mar 24, 2015 at 10:44:24AM +0000, Morten Rasmussen wrote:
> > > > Maybe remind us why this needs to be tied to sched_groups ? Why can't we
> > > > attach the energy information to the domains?
> 
> > In the current domain hierarchy you don't have domains with just one cpu
> > in them. If you attach the per-cpu energy data to the MC level domain
> > which spans the whole cluster, you break the current idea of attaching
> > information to the cpumask (currently sched_group, but could be
> > sched_domain as we discuss here) the information is associated with. You
> > would have to either introduce a level of single cpu domains at the
> > lowest level or move away from the idea of attaching data to the cpumask
> > that is associated with it.
> > 
> > Using sched_groups we do already have single cpu groups that we can
> > attach per-cpu data to, but we are missing a top level group spanning
> > the entire system for system wide energy data. So from that point of
> > view groups and domains are equally bad.
> 
> Oh urgh, good point that. Cursed if you do, cursed if you don't. Bugger.

Yeah :( I don't really care which one we choose. Adding another top
level domain with one big group spanning all cpus, but with all SD flags
disabled seems less intrusive than adding a level at the bottom.

Better ideas are very welcome.
--
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/