From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268242AbUHFTb0 (ORCPT ); Fri, 6 Aug 2004 15:31:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268244AbUHFT2i (ORCPT ); Fri, 6 Aug 2004 15:28:38 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:15627 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S268247AbUHFT1v (ORCPT ); Fri, 6 Aug 2004 15:27:51 -0400 Date: Fri, 6 Aug 2004 20:27:47 +0100 From: Russell King To: Hamie Cc: linux-kernel@vger.kernel.org Subject: Re: ide-cs using 100% CPU Message-ID: <20040806202747.H13948@flint.arm.linux.org.uk> Mail-Followup-To: Hamie , linux-kernel@vger.kernel.org References: <40FA4328.4060304@travellingkiwi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <40FA4328.4060304@travellingkiwi.com>; from hamish@travellingkiwi.com on Sun, Jul 18, 2004 at 10:30:16AM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 18, 2004 at 10:30:16AM +0100, Hamie wrote: > Anyone know why this happens? Something busy waiting? (BUt that should > show as system cpu right?) or something taking out really long locks? It'll be because IDE is using PIO to access the CF card, which could have long access times (so reading a block of sectors could take some time _and_ use CPU.) Obviously, PIO requires the use of the CPU, so the CPU can't be handed off to some other task while this is occuring. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/ 2.6 Serial core