Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030243AbWIFXa5 (ORCPT ); Wed, 6 Sep 2006 19:30:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030244AbWIFXa4 (ORCPT ); Wed, 6 Sep 2006 19:30:56 -0400 Received: from smtp19.orange.fr ([80.12.242.18]:24403 "EHLO smtp-msa-out19.orange.fr") by vger.kernel.org with ESMTP id S1030243AbWIFXaz (ORCPT ); Wed, 6 Sep 2006 19:30:55 -0400 X-ME-UUID: 20060906233054693.A954F1C000A6@mwinf1918.orange.fr From: Vincent Pelletier To: linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched.c: Be a bit more conservative in SMP Date: Thu, 7 Sep 2006 01:30:53 +0200 User-Agent: KMail/1.9.4 References: <200609031541.39984.subdino2004@yahoo.fr> <200609031910.57259.vincent.plr@wanadoo.fr> In-Reply-To: <200609031910.57259.vincent.plr@wanadoo.fr> Cc: mingo@elte.hu MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <200609070130.53995.vincent.plr@wanadoo.fr> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 892 Lines: 17 I found one maybe-drawback to this change : When runing n+1 process (n = number of cpu), one takes one cpu, the other 2 share another cpu. And, because of this patch, all processes stay in their own cpu, so one always has 100% of cpu power, the 2 others get 50% each. In current implementation, one of the 2 processes from the same cpu would migrate to the other cpu, and so on, somehow sharing cpu time among them. Is it a feature or a side effect of current implementation ? I'll do some tests soon to see which version gives better performance at a higher level than just process migration cost - if different at all. -- Vincent Pelletier - 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/