From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 09/12] irq: implement IRQ expecting Date: Thu, 17 Jun 2010 17:54:48 +0200 Message-ID: <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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100617124343.5889067c@lxorguk.ukuu.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: Alan Cox Cc: Thomas Gleixner , Arjan van de Ven , 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 List-Id: linux-ide@vger.kernel.org On 06/17/2010 01:43 PM, Alan Cox wrote: > On Thu, 17 Jun 2010 13:23:27 +0200 > Tejun Heo wrote: > >> On 06/17/2010 01:12 PM, Thomas Gleixner wrote: >>>> Hmmm.... oh, I see. Wouldn't it be much better to use moving avg of >>>> IRQ durations instead of letting the driver specify it? Drivers are >>>> most likely to just hard code it and It's never gonna be accurate. >>> >>> Right, but that's probably more accurate than the core code heuristics >>> ever will be. >> >> Eh, not really. For ATA at least, there will be three different >> classes of devices. SSDs, hard drives and optical devices > > At least four: It may also be battery backed RAM. Yeah, right, there are those crazy devices too but I think they would fall in a single tick any way. At any rate, let's say I have those numbers, how would I feed it into c-state selection? Thanks. -- tejun