linux-kernel - Re: [RFC PATCH 15/15] nohz

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1293011504.2170.76.camel@laptop>
Date:	Wed, 22 Dec 2010 10:51:44 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Avi Kivity <avi@...hat.com>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...e.hu>,
	Steven Rostedt <rostedt@...dmis.org>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Anton Blanchard <anton@....ibm.com>,
	Tim Pepper <lnxninja@...ux.vnet.ibm.com>
Subject: Re: [RFC PATCH 15/15] nohz_task: Procfs interface

On Wed, 2010-12-22 at 11:22 +0200, Avi Kivity wrote:
> > Makes sense. And that integrates well with Peter's idea of creating a
> > new cpuset attribute for the nohz tasks.
> >
> > But instead of making this detection from the scheduler, I think this
> > should be done from the tick: if there is only one task running, set
> > it the TF flag.
> >
> > But anyway, that's an optimisation. We can start with setting that flag
> > on every task in that cpuset.
> 
> So long as we start without the new knob. 

Right, so one of the things we can do is let the tick disable itself
when it finds there is no pending work left and set the TIF bit when
needed. We should then also rate-limit things so as not to
enable/disable the tick too often, but that would potentially allow us
to do away with all knobs.
--
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/