Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932689AbYB2Ne6 (ORCPT ); Fri, 29 Feb 2008 08:34:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755964AbYB2Net (ORCPT ); Fri, 29 Feb 2008 08:34:49 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:58730 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752762AbYB2Net (ORCPT ); Fri, 29 Feb 2008 08:34:49 -0500 Date: Fri, 29 Feb 2008 14:34:33 +0100 From: Ingo Molnar To: huggie@earth.li, linux-kernel@vger.kernel.org Cc: Thomas Gleixner Subject: Re: Scheduler broken? sdhci issues with scheduling Message-ID: <20080229133433.GA15532@elte.hu> References: <20080229115256.GG24533@paranoidfreak.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080229115256.GG24533@paranoidfreak.co.uk> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1312 Lines: 45 * Simon Huggins wrote: > [ Please Cc me on replies ] > > I had a bug with sdhci which Pierre Ossman looked at for me. > > In the end essentially the fix was to use HZ=1000 and nothing else. > Pierre seemed to think that this was a bug in the scheduler. does the patch below help, even if you keep HZ=100? This doesnt look like a scheduler issue, it's more of a timer/timing issue. Different HZ means different msleep() results - and the mmc code does a loop of small msleep delays. Ingo --------------> --- drivers/mmc/core/core.h | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) Index: linux/drivers/mmc/core/core.h =================================================================== --- linux.orig/drivers/mmc/core/core.h +++ linux/drivers/mmc/core/core.h @@ -36,12 +36,7 @@ void mmc_set_timing(struct mmc_host *hos static inline void mmc_delay(unsigned int ms) { - if (ms < 1000 / HZ) { - cond_resched(); - mdelay(ms); - } else { - msleep(ms); - } + mdelay(ms); } void mmc_rescan(struct work_struct *work); -- 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/