From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752573AbXDDXAB (ORCPT ); Wed, 4 Apr 2007 19:00:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752582AbXDDXAA (ORCPT ); Wed, 4 Apr 2007 19:00:00 -0400 Received: from ozlabs.org ([203.10.76.45]:41771 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752573AbXDDW77 (ORCPT ); Wed, 4 Apr 2007 18:59:59 -0400 Subject: Re: [patch 04/17] Add pagetable accessors to pack and unpack pagetable entries From: Rusty Russell To: Andi Kleen Cc: Jeremy Fitzhardinge , virtualization@lists.osdl.org, Andrew Morton , Ingo Molnar , lkml In-Reply-To: <200704041756.35016.ak@suse.de> References: <20070402055652.610711908@goop.org> <200704041347.42822.ak@suse.de> <4613C828.2030604@goop.org> <200704041756.35016.ak@suse.de> Content-Type: text/plain Date: Thu, 05 Apr 2007 08:59:09 +1000 Message-Id: <1175727549.12230.583.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-04-04 at 17:56 +0200, Andi Kleen wrote: > On Wednesday 04 April 2007 17:45:44 Jeremy Fitzhardinge wrote: > > Andi Kleen wrote: > > > Why is there a difference for null syscall? I had assumed we patched all the > > > fast path cases relevant there. Do you have an idea where it comes from? > > > > Sure. There's indirect calls for things like sti/cli/iret. It goes > > back to native speed when you patch the real instructions inline. > > I was talking about the patched case. It seemed to be a little slower > too, but in theory it shouldn't have been, no? You'll still have the damage inflicted on gcc's optimizer, though. Rusty.