From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965971AbXCPVwH (ORCPT ); Fri, 16 Mar 2007 17:52:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965974AbXCPVwH (ORCPT ); Fri, 16 Mar 2007 17:52:07 -0400 Received: from [212.12.190.214] ([212.12.190.214]:32924 "EHLO raad.intranet" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S965971AbXCPVwF (ORCPT ); Fri, 16 Mar 2007 17:52:05 -0400 From: Al Boldi To: linux-kernel@vger.kernel.org Subject: decrease L2 cache size used by Linux? Date: Sat, 17 Mar 2007 00:55:27 +0300 User-Agent: KMail/1.5 MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <200703170055.27126.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Guerreiro da Luz wrote: > Am benchmarking dumb matrix multiplication in trying to perceive > performance drop in case when matrix cannot fit in L2 cache. However, > on my machine L2 cache is large - 2MB, so 512x512 matrix of double > numbers is needed to fill the cache, and in that case multiplication > is taking rather long time. So I'm wondering is there a way to > control (decrease) L2 cache size used by Linux? Apologies if question > inappropriate for the list. You may want to turn off randomization, echo 0 > /proc/sys/kernel/randomize_va_space echo 1 > /proc/sys/vm/vdso_enabled And see if that helps. Thanks! -- Al