Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 29 Jul 2002 20:53:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 29 Jul 2002 20:53:58 -0400 Received: from brynhild.MtRoyal.AB.CA ([142.109.10.24]:61918 "EHLO brynhild.mtroyal.ab.ca") by vger.kernel.org with ESMTP id ; Mon, 29 Jul 2002 20:53:57 -0400 Date: Mon, 29 Jul 2002 18:56:57 -0600 (MDT) From: James Bourne To: Andrew Theurer cc: Alan Cox , , Marcelo Tosatti Subject: Re: Linux 2.4.19-rc3 (hyperthreading) In-Reply-To: <200207291842.16145.habanero@us.ibm.com> Message-ID: MIME-Version: 1.0 X-scanner: scanned by Inflex 1.0.12.2 - (http://pldaniels.com/inflex/) Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3094 Lines: 71 On Mon, 29 Jul 2002, Andrew Theurer wrote: > On Monday 29 July 2002 7:37 pm, Alan Cox wrote: > > On Mon, 2002-07-29 at 21:58, Andrew Theurer wrote: > > > Agreed, we need some sort of irqbalance, and I intend to test with Ingo's > > > and Andrea's approaches. With that addition, I may even see an > > > improvement with hyperthreading. But for an rc release, I think it would > > > be prudent to revert the "new code" for default hyperthreading behavior, > > > and attack the whole problem in 2.4.20 or later release. > > > > Because your personal workload is slower ? > > Well, I would think some here would be interested in samba performance. > However, If 4-way P4 systems are considered rare at this point I guess it's > not important enough to revert. FYI, after testing 2P with and without > hyperthreading, it's much faster. 481 Mbps for no hyperthreading and 605 > Mbps with. If I can get even close to that improvement with 4 processors, > I'll be very happy. Hyperthreading only helps if you are running a process when uses a lot of concurrent process binding up CPU time (IE, more runnable processes waiting then there are CPUs). I/O won't be much effected, and I found that it actually gave a performance hit to turn it on if you weren't using it (about 5%, maybe) if you are not utilizing the existing processors. Of course, if you are already talking a single, dual, or quad P4 at 1.8GHz or something, 5% sounds like a lot, but if you're not using it that heavily you won't actually notice the 5% loss in performance (well, unless you are watching some kind of image rendering software do it's thing? =). Some tests I performed in April are at http://www.hardrock.org/HT-results/ You can see in the kernel compile output the difference. Regards James Bourne > > -Andrew Theurer > > - > 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/ > -- James Bourne, Supervisor Data Centre Operations Mount Royal College, Calgary, AB, CA www.mtroyal.ab.ca ****************************************************************************** This communication is intended for the use of the recipient to which it is addressed, and may contain confidential, personal, and or privileged information. Please contact the sender immediately if you are not the intended recipient of this communication, and do not copy, distribute, or take action relying on it. Any communication received in error, or subsequent reply, should be deleted or destroyed. ****************************************************************************** "There are only 10 types of people in this world: those who understand binary and those who don't." - 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/