From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763759AbXGFPue (ORCPT ); Fri, 6 Jul 2007 11:50:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757220AbXGFPu0 (ORCPT ); Fri, 6 Jul 2007 11:50:26 -0400 Received: from gateway-1237.mvista.com ([63.81.120.158]:2251 "EHLO gateway-1237.mvista.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761098AbXGFPu0 (ORCPT ); Fri, 6 Jul 2007 11:50:26 -0400 Subject: Re: [RFC] Thread Migration Preemption From: Daniel Walker To: Steven Rostedt Cc: Nick Piggin , Mathieu Desnoyers , Ingo Molnar , linux-kernel@vger.kernel.org In-Reply-To: <1183732495.17319.133.camel@localhost.localdomain> References: <20070705215152.GA4865@Krystal> <468DDD3A.6010308@yahoo.com.au> <1183732495.17319.133.camel@localhost.localdomain> Content-Type: text/plain Date: Fri, 06 Jul 2007 08:43:39 -0700 Message-Id: <1183736619.19602.7.camel@imap.mvista.com> Mime-Version: 1.0 X-Mailer: Evolution 2.10.2 (2.10.2-2.fc7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2007-07-06 at 10:34 -0400, Steven Rostedt wrote: > thing is that in RT an IRQ thread might service a softirq if that > softirq thread is of the same priority as the IRQ thread. The difference > between an IRQ thread and a softirq thread is that the IRQ thread may > migrate but the softirq thread may not. So to do this performance > enhancement, we need to temporarily pin the IRQ thread to the CPU, which > is expensive (set_cpus_allowed). This would make it much simpler and > light weight to implement. Are there any other reasons? Daniel