Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965373AbVKHDwp (ORCPT ); Mon, 7 Nov 2005 22:52:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965377AbVKHDwp (ORCPT ); Mon, 7 Nov 2005 22:52:45 -0500 Received: from smtp200.mail.sc5.yahoo.com ([216.136.130.125]:23634 "HELO smtp200.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S965373AbVKHDwo (ORCPT ); Mon, 7 Nov 2005 22:52:44 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=JWX/8TNtDTtqnrFnO3VXQdTHC7o429+hzqmi75CNX91Nv9a5Qj1v/BBYgdzSepdrcIwlsN12/pnpV8USuewXcrCBWcLHSC4wcMNC+6et1ntxF7PIcipci+PLQT1aGxye2LJFfZehy+feYvXcLTEpw1CXe/gVZ0vRy01Zqb48r6Y= ; Message-ID: <4370217F.3090807@yahoo.com.au> Date: Tue, 08 Nov 2005 14:54:39 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: "linux-os (Dick Johnson)" CC: Brian Twichell , linux-kernel@vger.kernel.org, mbligh@mbligh.org, slpratt@us.ibm.com, anton@samba.org Subject: Re: Database regression due to scheduler changes ? References: <436FD291.2060301@us.ibm.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1127 Lines: 33 linux-os (Dick Johnson) wrote: > > Can you change sched_yield() to usleep(1) or usleep(0) and see if > that works. I found that in recent kernels sched_yield() just seems > to spin (may not actually spin, but seems to with a high CPU usage). > I've told you that it *does* spin and always has. Even with 2.4 kernels. In fact, it is *specified* to spin, anything else would be a bug. Caveat: it also yields the CPU, but only if there is another runnable task with a higher priority (which is meaningless between SCHED_OTHER tasks, though we try to do something sane there too). Secondly, Brian actually pinpointed the source of the regression and it is not sched_yield(), nor has sched_yield changed since the regression. So wouldn't this just be a wild goose chase. Nick -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com - 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/