Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750976AbWCUC7i (ORCPT ); Mon, 20 Mar 2006 21:59:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751471AbWCUC7h (ORCPT ); Mon, 20 Mar 2006 21:59:37 -0500 Received: from mail.parknet.jp ([210.171.160.80]:47876 "EHLO parknet.jp") by vger.kernel.org with ESMTP id S1750976AbWCUC7h (ORCPT ); Mon, 20 Mar 2006 21:59:37 -0500 X-AuthUser: hirofumi@parknet.jp To: kernel@kolivas.org Cc: Andreas Mohr , bert hubert , linux-kernel@vger.kernel.org, george@mvista.com Subject: Re: gettimeofday order of magnitude slower with pmtimer, which is default References: <20060320122449.GA29718@outpost.ds9a.nl> <20060320145047.GA12332@rhlx01.fht-esslingen.de> <200603210224.23540.kernel@kolivas.org> <87wteo37vr.fsf@duaron.myhome.or.jp> <1142901656.441f4b98472e5@vds.kolivas.org> From: OGAWA Hirofumi Date: Tue, 21 Mar 2006 11:59:29 +0900 In-Reply-To: <1142901656.441f4b98472e5@vds.kolivas.org> (kernel@kolivas.org's message of "Tue, 21 Mar 2006 11:40:56 +1100") Message-ID: <87acbk33la.fsf@duaron.myhome.or.jp> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1220 Lines: 35 kernel@kolivas.org writes: > Quoting OGAWA Hirofumi : > > What I mean is that I've seen profiles of the worst (from Andi) showing up to 5% > cpu time on some workloads! That's a heck of a lot slower than when it's > latched. I see. Thanks. >> + if (unlikely(pmtmr_need_workaround)) { > > I would not put this in an unlikely because on the machines where > pmtmr_need_workaround is true this will always be true. Yes. However, if machines uses buggy chip, I guessed TSC/PIT would be more proper as time source. But probably you are right, timer_pit.c seems more slow usually (it uses many I/O port). I'll remove unlikely(), and also will remove "Use other timer source" from warning. BTW, this patch is still quick hack. At least, we would need to check the ICH4 which says in comment. However, I couldn't find the PM-Timer Errata in ICH4 spec update. Do you/anyone know about a ICH4 error? -- OGAWA Hirofumi - 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/