From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261179AbVGGGh1 (ORCPT ); Thu, 7 Jul 2005 02:37:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261181AbVGGGh0 (ORCPT ); Thu, 7 Jul 2005 02:37:26 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:3511 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S261179AbVGGGhY (ORCPT ); Thu, 7 Jul 2005 02:37:24 -0400 Subject: Re: Slowdown with randomize_va_space in 2.6.12.2 From: Arjan van de Ven To: Andrew Morton Cc: Dave Jones , davem@davemloft.net, pmarques@grupopie.com, linux-kernel@vger.kernel.org In-Reply-To: <20050706181220.3978d7f6.akpm@osdl.org> References: <42CBE97C.2060208@grupopie.com> <20050706.125719.08321870.davem@davemloft.net> <20050706205315.GC27630@redhat.com> <20050706181220.3978d7f6.akpm@osdl.org> Content-Type: text/plain Date: Thu, 07 Jul 2005 08:37:08 +0200 Message-Id: <1120718229.3198.8.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 (2.2.2-5) Content-Transfer-Encoding: 7bit X-Spam-Score: 3.7 (+++) X-Spam-Report: SpamAssassin version 2.63 on pentafluge.infradead.org summary: Content analysis details: (3.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 1.1 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] 2.5 RCVD_IN_DYNABLOCK RBL: Sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 0.1 RCVD_IN_SORBS RBL: SORBS: sender is listed in SORBS [80.57.133.107 listed in dnsbl.sorbs.net] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2005-07-06 at 18:12 -0700, Andrew Morton wrote: > Dave Jones wrote: > > > > On Wed, Jul 06, 2005 at 12:57:19PM -0700, David S. Miller wrote: > > > From: Paulo Marques > > > Date: Wed, 06 Jul 2005 15:23:56 +0100 > > > > > > > What is weird is that most of the extra time is being accounted as > > > > user-space time, but the user-space application is exactly the same in > > > > both runs, only the "randomize_va_space" parameter changed. > > > > > > It might be attributable to more cpu cache misses in userspace since > > > the virtual addresses of everything are changing each and every > > > invocation. > > > > On Transmeta CPUs that probably triggers a retranslation of > > x86->native bytecode, if it thinks it hasn't seen code at that > > address before. > > > > ouch. What do we do? Default to off? Default to off on xmeta? off-on-xmeta would be my preference; I'll cook up a patch for that.