Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 4 Oct 2001 17:39:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 4 Oct 2001 17:39:25 -0400 Received: from vindaloo.ras.ucalgary.ca ([136.159.55.21]:33155 "EHLO vindaloo.ras.ucalgary.ca") by vger.kernel.org with ESMTP id ; Thu, 4 Oct 2001 17:39:17 -0400 Date: Thu, 4 Oct 2001 15:39:05 -0600 Message-Id: <200110042139.f94Ld5r09675@vindaloo.ras.ucalgary.ca> From: Richard Gooch To: "David S. Miller" Cc: arjan@fenrus.demon.nl, kravetz@us.ibm.com, linux-kernel@vger.kernel.org Subject: Re: Context switch times In-Reply-To: <20011004.142523.54186018.davem@redhat.com> In-Reply-To: <20011004140417.C1245@w-mikek2.des.beaverton.ibm.com> <20011004.142523.54186018.davem@redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org David S. Miller writes: > From: arjan@fenrus.demon.nl > Date: Thu, 04 Oct 2001 22:14:13 +0100 > > > Comments? > > 2.4.x supports SSE on pentium III/athlons, so the SSE registers need to be > saved/restored on a taskswitch as well.... that's not exactly free. > > lat_ctx doesn't execute any FPU ops. So at worst this happens once > on GLIBC program startup, but then never again. Has something changed? Last I looked, the whole lmbench timing harness was based on using the FPU. That was the cause of the big argument Larry and I had some years back: my context switch benchmark didn't use the FPU, and thus was more sensitive to variations (such as cache misses due to aliasing). Regards, Richard.... Permanent: rgooch@atnf.csiro.au Current: rgooch@ras.ucalgary.ca - 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/