Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262495AbVEMTQD (ORCPT ); Fri, 13 May 2005 15:16:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262491AbVEMTOz (ORCPT ); Fri, 13 May 2005 15:14:55 -0400 Received: from colin.muc.de ([193.149.48.1]:8967 "EHLO mail.muc.de") by vger.kernel.org with ESMTP id S262487AbVEMTII (ORCPT ); Fri, 13 May 2005 15:08:08 -0400 Date: 13 May 2005 21:08:07 +0200 Date: Fri, 13 May 2005 21:08:07 +0200 From: Andi Kleen To: Scott Robert Ladd Cc: Alan Cox , Gabor MICSKO , Linux Kernel Mailing List Subject: Re: Hyper-Threading Vulnerability Message-ID: <20050513190807.GC47131@muc.de> References: <1115963481.1723.3.camel@alderaan.trey.hu> <1116009347.1448.489.camel@localhost.localdomain> <4284F6B5.2080308@coyotegulch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4284F6B5.2080308@coyotegulch.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 942 Lines: 22 On Fri, May 13, 2005 at 02:49:25PM -0400, Scott Robert Ladd wrote: > Alan Cox wrote: > > HT for most users is pretty irrelevant, its a neat idea but the > > benchmarks don't suggest its too big a hit > > On real-world applications, I haven't seen HT boost performance by more > than 15% on a Pentium 4 -- and the usual gain is around 5%, if anything > at all. HT is a nice idea, but I don't enable it on my systems. I saw better improvement in some cases. It always depends on the workload. And on the generation of HT (there are three around). And lots of other factors. Even for your workload only it does not seem to me to be very rational to throw away a 15% speedup with open eyes. -Andi - 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/