Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760282Ab0FQQC4 (ORCPT ); Thu, 17 Jun 2010 12:02:56 -0400 Received: from casper.infradead.org ([85.118.1.10]:49130 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756416Ab0FQQCy (ORCPT ); Thu, 17 Jun 2010 12:02:54 -0400 Date: Thu, 17 Jun 2010 09:02:29 -0700 From: Arjan van de Ven To: Tejun Heo Cc: Alan Cox , Thomas Gleixner , mingo@elte.hu, bphilips@suse.de, yinghai@kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, jeff@garzik.org, linux-ide@vger.kernel.org, stern@rowland.harvard.edu, gregkh@suse.de, khali@linux-fr.org Subject: Re: [PATCH 09/12] irq: implement IRQ expecting Message-ID: <20100617090229.543af62c@infradead.org> In-Reply-To: <4C1A4548.3020602@kernel.org> References: <1276443098-20653-1-git-send-email-tj@kernel.org> <1276443098-20653-10-git-send-email-tj@kernel.org> <20100616204854.4b036f87@infradead.org> <4C19DA64.8000409@kernel.org> <4C1A05AF.5010405@kernel.org> <20100617124343.5889067c@lxorguk.ukuu.org.uk> <4C1A4548.3020602@kernel.org> Organization: Intel X-Mailer: Claws Mail 3.7.6 (GTK+ 2.20.1; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1168 Lines: 31 On Thu, 17 Jun 2010 17:54:48 +0200 Tejun Heo wrote: > Crazy devices too but I think they would > fall in a single tick any way. not sure what ticks have to do with anything but ok ;) > At any rate, let's say I have those > numbers, how would I feed it into c-state selection? if we have this, we need to put a bit of glue in the backend that tracks (per cpu I suppose) the shortest expected interrupt, which the C state code then queries. (and in that regard, it does not matter if shortest expected is computed via heuristic on a per irq basis, or passed in). mapping an irq to a cpu is not a 100% science (since interrupts can move in theory), but just assuming that the irq will happen on the same CPU it happened last time is more than good enough. -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/