Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750817AbWI0Im1 (ORCPT ); Wed, 27 Sep 2006 04:42:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750711AbWI0Im1 (ORCPT ); Wed, 27 Sep 2006 04:42:27 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:19605 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1750817AbWI0Im0 (ORCPT ); Wed, 27 Sep 2006 04:42:26 -0400 Date: Wed, 27 Sep 2006 10:34:19 +0200 From: Ingo Molnar To: Mike Kravetz Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , John Stultz , "Paul E. McKenney" , Dipankar Sarma , Arjan van de Ven Subject: Re: 2.6.18-rt1 Message-ID: <20060927083419.GC12149@elte.hu> References: <20060920141907.GA30765@elte.hu> <20060925161215.GA19230@w-mikek2.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060925161215.GA19230@w-mikek2.ibm.com> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1347 Lines: 31 * Mike Kravetz wrote: > On Wed, Sep 20, 2006 at 04:19:07PM +0200, Ingo Molnar wrote: > > In particular, a nasty softirq performance bug has been fixed, which > > caused the "5x slowdown under TCP" bug reported to lkml - those TCP > > performance figures are now on par with vanilla performance. > > Just curious about the cause and fix for this issue. I tried > searching the mail lists for discussion but came up empty. The patch > it too big for me to determine what specific changes addressed this > issue. If anyone can point me in the right direction, that would be > appreciated. i /think/ it's this bit of code commented out in kernel/softirq.c: //if (!in_interrupt() && local_softirq_pending()) // invoke_softirq(); try to uncomment that. (this should i think do the trick on PREEMPT_RT - but no guarantees. It might cause problems on !PREEMPT_RT configs, i had to juggle around some code here. Maybe the easiest would be if you tried to take the new softirq.c, sans the lockdep changes. Not sure how feasible that is though.) Ingo - 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/