linux-kernel - Re: [RFC PATCH 2/3] sched: add yield

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:	Fri, 03 Dec 2010 16:09:47 +0100
From:	Mike Galbraith <efault@....de>
To:	Rik van Riel <riel@...hat.com>
Cc:	vatsa@...ux.vnet.ibm.com, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Avi Kiviti <avi@...hat.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>,
	Anthony Liguori <aliguori@...ux.vnet.ibm.com>
Subject: Re: [RFC PATCH 2/3] sched: add yield_to function

On Fri, 2010-12-03 at 09:48 -0500, Rik van Riel wrote:
> On 12/03/2010 09:45 AM, Mike Galbraith wrote:
> 
> > I'll have to go back and re-read that.  Off the top of my head, I see no
> > way it could matter which container the numbers live in as long as they
> > keep advancing, and stay in the same runqueue.  (hm, task weights would
> > have to be the same too or scaled. dangerous business, tinkering with
> > vruntimes)
> 
> They're not necessarily in the same runqueue, the
> VCPU that is given time might be on another CPU
> than the one that was spinning on a lock.

I don't think pumping vruntime cross cfs_rq would be safe, for the
reason noted (et al).  No competition means vruntime is meaningless.
Donating just advances a clock that nobody's looking at.

	-Mike

--
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/