From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752716AbZHBMuy (ORCPT ); Sun, 2 Aug 2009 08:50:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752687AbZHBMux (ORCPT ); Sun, 2 Aug 2009 08:50:53 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:47912 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752054AbZHBMuw (ORCPT ); Sun, 2 Aug 2009 08:50:52 -0400 Date: Thu, 30 Jul 2009 11:07:47 +0200 From: Pavel Machek To: Thomas Hellstrom Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, venkatesh.pallipadi@intel.com Subject: Re: [PATCH] x86: Use clflush() instead of wbinvd() whenever possible when changing mapping Message-ID: <20090730090747.GD1364@ucw.cz> References: <1248421981-31865-1-git-send-email-thellstrom@vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1248421981-31865-1-git-send-email-thellstrom@vmware.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 2009-07-24 09:53:01, Thomas Hellstrom wrote: > The current code uses wbinvd() when the area to flush is > 4MB. Although this > may be faster than using clflush() the effect of wbinvd() on irq > latencies You are slowing the kernel down, and you did not write down the reasons. bad. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html