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 13:23:27 +0200 Message-ID: <4C1A05AF.5010405@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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:35732 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750701Ab0FQLYg (ORCPT ); Thu, 17 Jun 2010 07:24:36 -0400 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Thomas Gleixner Cc: 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 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 and if we get running avg w/ fairly large stability part, the numbers wouldn't be too far off and there's no reliable way for the driver to tell which type of device is on the other side of the cable. So, I think running avg would work much better. Thanks. -- tejun