linux-kernel - Re: [RFC] sched: CPU topology try

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: <20140108133329.GL2936@e103034-lin>
Date:	Wed, 8 Jan 2014 13:33:29 +0000
From:	Morten Rasmussen <morten.rasmussen@....com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Alex Shi <alex.shi@...aro.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <Dietmar.Eggemann@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"mingo@...nel.org" <mingo@...nel.org>,
	"pjt@...gle.com" <pjt@...gle.com>,
	"cmetcalf@...era.com" <cmetcalf@...era.com>,
	"tony.luck@...el.com" <tony.luck@...el.com>,
	"preeti@...ux.vnet.ibm.com" <preeti@...ux.vnet.ibm.com>,
	"linaro-kernel@...ts.linaro.org" <linaro-kernel@...ts.linaro.org>,
	"paulmck@...ux.vnet.ibm.com" <paulmck@...ux.vnet.ibm.com>,
	"corbet@....net" <corbet@....net>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"len.brown@...el.com" <len.brown@...el.com>,
	"arjan@...ux.intel.com" <arjan@...ux.intel.com>,
	"amit.kucheria@...aro.org" <amit.kucheria@...aro.org>,
	"james.hogan@...tec.com" <james.hogan@...tec.com>,
	"schwidefsky@...ibm.com" <schwidefsky@...ibm.com>,
	"heiko.carstens@...ibm.com" <heiko.carstens@...ibm.com>
Subject: Re: [RFC] sched: CPU topology try

On Wed, Jan 08, 2014 at 01:04:07PM +0000, Peter Zijlstra wrote:
> On Wed, Jan 08, 2014 at 12:52:28PM +0000, Morten Rasmussen wrote:
> 
> > If I remember correctly, Alex used the rq runnable_avg_sum (in rq->avg)
> > for this. It is the most obvious choice, but it takes ages to reach
> > 100%.
> > 
> > #define LOAD_AVG_MAX_N 345
> > 
> > Worst case it takes 345 ms from the system is becomes fully utilized
> > after a long period of idle until the rq runnable_avg_sum reaches 100%.
> > 
> > An unweigthed version of cfs_rq->runnable_load_avg and blocked_load_avg
> > wouldn't have that delay.
> 
> Right.. not sure we want to involve blocked load on the utilization
> metric, but who knows maybe that does make sense.
> 
> But yes, we need unweighted runnable_avg.

I'm not sure about the blocked load either.

> 
> > Also, if we are changing the load balance behavior when all cpus are
> > fully utilized
> 
> We already have this tipping point. See all the has_capacity bits. But
> yes, it'd get more involved I suppose.

I'll have a look.
--
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/