From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751380AbWFBKNE (ORCPT ); Fri, 2 Jun 2006 06:13:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751385AbWFBKNE (ORCPT ); Fri, 2 Jun 2006 06:13:04 -0400 Received: from mail28.syd.optusnet.com.au ([211.29.133.169]:56736 "EHLO mail28.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S1751380AbWFBKNC (ORCPT ); Fri, 2 Jun 2006 06:13:02 -0400 From: Con Kolivas To: "Chen, Kenneth W" Subject: Re: [PATCH RFC] smt nice introduces significant lock contention Date: Fri, 2 Jun 2006 20:12:44 +1000 User-Agent: KMail/1.9.1 Cc: "'Nick Piggin'" , linux-kernel@vger.kernel.org, "'Chris Mason'" , "Ingo Molnar" References: <000001c6862a$5d7142d0$114ce984@amr.corp.intel.com> In-Reply-To: <000001c6862a$5d7142d0$114ce984@amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200606022012.44866.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday 02 June 2006 19:53, Chen, Kenneth W wrote: > Yeah, but that is the worst case though. Average would probably be a lot > lower than worst case. Also, on smt it's not like the current logical cpu > is getting blocked because of another task is running on its sibling CPU. > The hardware still guarantees equal share of hardware resources for both > logical CPUs. "Equal share of hardware resources" is exactly the problem; they shouldn't have equal share since they're sharing one physical cpu's resources. It's a relative breakage of the imposed nice support and I disagree with your conclusion. -- -ck