linux-kernel - Re: suspend blockers & Android integration

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Message-ID: <alpine.LFD.2.00.1006032141060.8175@i5.linux-foundation.org>
Date:	Thu, 3 Jun 2010 21:46:01 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Arjan van de Ven <arjan@...radead.org>
cc:	Ingo Molnar <mingo@...e.hu>, tytso@....edu,
	Brian Swetland <swetland@...gle.com>,
	Neil Brown <neilb@...e.de>, Arve Hj?nnev?g <arve@...roid.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Alan Stern <stern@...land.harvard.edu>,
	Felipe Balbi <felipe.balbi@...ia.com>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Florian Mickler <florian@...kler.org>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Linux PM <linux-pm@...ts.linux-foundation.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	James Bottomley <James.Bottomley@...e.de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Kevin Hilman <khilman@...prootsystems.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: suspend blockers & Android integration



On Thu, 3 Jun 2010, Arjan van de Ven wrote:
> 
> And because there's then no power saving (but a performance cost), it's
> actually a negative for battery life/total energy.

Including the UP optimizations we do (ie lock prefix removal)? It's 
possible that I'm just biased by benchmarks, and it's true that Intel has 
been getting lots better, but the locking costs are very noticeable 
performance-wise on some benchmarks.

And several CPU's have been held back from going into deepest sleep states 
by stupid firmware and/or platform bugs.

But hey, if it's not going to help, and people have tried it, I guess I'll 
have to believe it.

		Linus

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