From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: 2.6.24 BUG: soft lockup - CPU#X Date: Fri, 28 Mar 2008 15:12:48 +0100 Message-ID: <20080328141246.GD29218@elte.hu> References: <47EC399E.90804@sun.com> <20080327.173418.18777696.davem@davemloft.net> <20080328012234.GA20465@gondor.apana.org.au> <20080327.183844.74572930.davem@davemloft.net> <20080328102931.GA23039@gondor.apana.org.au> <20080328105629.GG1011@elte.hu> <20080328110621.GA23342@gondor.apana.org.au> <20080328112928.GA23547@gondor.apana.org.au> <1206706759.4429.58.camel@localhost> <20080328132643.GA24180@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: jamal , "David S. Miller" , Matheos.Worku@Sun.COM, jesse.brandeburg@intel.com, jarkao2@gmail.com, netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from mx3.mail.elte.hu ([157.181.1.138]:57286 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753060AbYC1ONO (ORCPT ); Fri, 28 Mar 2008 10:13:14 -0400 Content-Disposition: inline In-Reply-To: <20080328132643.GA24180@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: * Herbert Xu wrote: > I agree that using jiffies is a pretty coarse approximation of proper > scheduling. However, in the absence of a better solution we have to > live with it. > > Perhaps running these out of process context is the correct approach. yes. Such anonymous work loops inside softirq context are a disaster to TCP determinism and a disaster to scheduling in general (the wrong guy gets credited with the overhead). Softirqs were a neat hack 10 years ago, now if we know the target task for some workload we should execute as much of the workload in that task's context as possible. (and even for stuff where we dont have a 'target task' - routing, filtering, etc. - it might be better to use kernel threads.) Ingo