From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751306AbWAaSLA (ORCPT ); Tue, 31 Jan 2006 13:11:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751308AbWAaSLA (ORCPT ); Tue, 31 Jan 2006 13:11:00 -0500 Received: from ms-smtp-02.nyroc.rr.com ([24.24.2.56]:27055 "EHLO ms-smtp-02.nyroc.rr.com") by vger.kernel.org with ESMTP id S1751306AbWAaSK7 (ORCPT ); Tue, 31 Jan 2006 13:10:59 -0500 Subject: Re: CONFIG_PREEMPT_SOFTIRQS From: Steven Rostedt To: Vinod KK Cc: linux-kernel@vger.kernel.org In-Reply-To: References: Content-Type: text/plain Date: Tue, 31 Jan 2006 13:10:55 -0500 Message-Id: <1138731055.7088.26.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2006-01-31 at 20:19 +0530, Vinod KK wrote: > Hi, > > I am using linux 2.6.10 (with Ingo Molnars real time patches) on my mips board. > > When I try running high network traffic (10% traffic on a 100Mbps > link) on my target board with the CONFIG_PREEMPT_DESKTOP=y and > CONFIG_PREEMPT_SOFTIRQS=y options enabled I notice that the console > freezes and recovers only after the traffic stops. I do not notice > this behaviour with the CONFIG_PREEMPT_SOFTIRQS option disabled. > > I understand that the CONFIG_PREEMPT_SOFTIRQS option puts all softirq > processing to the ksoftirqd daemon, but i do not see why this should > stall the console. I believe there should be some task which is > starving for CPU, but I do not know which one. > > The console is on an 16550 serial port. > > Could someone please give me some pointers on where I should start looking? 2.6.10 with Ingo's patch is pretty old. The -rt patch is very much a moving target today and is not yet stable. So the only real answer I can give you is to go ahead and download http://people.redhat.com/mingo/realtime-preempt/patch-2.6.15-rt16 and try that out. -- Steve