Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 29 Jul 2002 16:09:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 29 Jul 2002 16:09:48 -0400 Received: from pc2-cwma1-5-cust12.swa.cable.ntl.com ([80.5.121.12]:23035 "EHLO irongate.swansea.linux.org.uk") by vger.kernel.org with ESMTP id ; Mon, 29 Jul 2002 16:09:47 -0400 Subject: Re: Linux 2.4.19-rc3 (hyperthreading) From: Alan Cox To: Andrew Theurer Cc: linux-kernel@vger.kernel.org, Marcelo Tosatti In-Reply-To: <200207291454.30076.habanero@us.ibm.com> References: <200207291454.30076.habanero@us.ibm.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.3 (1.0.3-6) Date: 29 Jul 2002 22:28:42 +0100 Message-Id: <1027978122.4050.22.camel@irongate.swansea.linux.org.uk> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1050 Lines: 20 On Mon, 2002-07-29 at 20:54, Andrew Theurer wrote: > I would caution against having hyperthreading on by default in the 2.4.19 > release. I am seeing a significant degrade in network workloads on P4 with > hyperthreading on. On 2.4.19-pre10, I get 788 Mbps on NetBench, but on > 2.4.19-rc1 (and probably rc3, should know in an hour), I get 690 Mbps. It is > clearly a hyperthreading/interrupt routing issue. On this system (4 x P4), Quite possibly. I've just merged the O(1) scheduler load balancing fixes for the hyperthreading stuff, rc3 uses the old scheduler so that isnt your problem. For most workloads I see a speed up. The more cache optimised the workload the less the speedup. Its quite possible the irq routing ought to be smarter, at the moment I'm not sure of the best approaches. - 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/