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: <alpine.LFD.2.00.1102242148400.2701@localhost6.localdomain6>
Date:	Thu, 24 Feb 2011 21:49:51 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Nicolas Pitre <nicolas.pitre@...aro.org>
cc:	Peter Zijlstra <peterz@...radead.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	lkml <linux-kernel@...r.kernel.org>,
	linux-hotplug@...r.kernel.org,
	Frederic Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>, amit.kucheria@...aro.org,
	Rusty Russell <rusty@...tcorp.com.au>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH V5 2/2] tracing, perf : add cpu hotplug trace events

On Thu, 24 Feb 2011, Nicolas Pitre wrote:

> On Thu, 24 Feb 2011, Peter Zijlstra wrote:
> 
> > On Thu, 2011-02-24 at 15:24 -0500, Nicolas Pitre wrote:
> > 
> > > Most SMP ARM processors are going to use it soon.  Powering down idle 
> > > cores provides substantial power saving.
> > 
> > And why can't regular idle paths be used? CPU hotplug is a massively
> > expensive operation.
> 
> The idle path assumes that the CPU state is preserved.  We're talking 
> about cores completely going down with power pulled beneath them and 
> eventually rebooted dynamically here.

That's the equivalent of physical hotplug, but we still have all the
memory state around, so it is possible from idle, when we have the
full isolation features in place.

Thanks,

	tglx
--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ