From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265361AbTL0LPI (ORCPT ); Sat, 27 Dec 2003 06:15:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265362AbTL0LPI (ORCPT ); Sat, 27 Dec 2003 06:15:08 -0500 Received: from c211-28-147-198.thoms1.vic.optusnet.com.au ([211.28.147.198]:62187 "EHLO mail.kolivas.org") by vger.kernel.org with ESMTP id S265361AbTL0LPF (ORCPT ); Sat, 27 Dec 2003 06:15:05 -0500 From: Con Kolivas To: Pavel Machek Subject: Re: [PATCH] 2.6.0 batch scheduling, HT aware Date: Sat, 27 Dec 2003 22:15:01 +1100 User-Agent: KMail/1.5.3 Cc: linux kernel mailing list , Nick Piggin References: <200312231138.21734.kernel@kolivas.org> <200312271042.55989.kernel@kolivas.org> <20031227110903.GA1413@elf.ucw.cz> In-Reply-To: <20031227110903.GA1413@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200312272215.01563.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 27 Dec 2003 22:09, Pavel Machek wrote: > So... even on normal SMP, > "task-on-other-cpu-slows-down-task-on-this-cpu" effect exists. Okay, > it is not as visible as on HT machine (50% slowdown), but its > definitely there. Sure but I think we're getting pedantic here. The problem is really simple - a uniprocessor HT desktop booted in SMP mode feels half the speed while running setiathome (or video encoding or whatever cpu bound task) compared to booting it in UP mode. So, ironically, enabling the HT makes the machine feel slower when running multiple tasks. And there will be a heck of a lot of these in the future. Con