From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable Date: 20 Mar 2007 21:02:42 +0100 Message-ID: <20070320200242.GA90774@muc.de> References: <1174348905.11680.54.camel@localhost.localdomain> <45FF4043.4000805@vmware.com> <45FF770C.7050301@goop.org> <20070320192818.GA87860@muc.de> <46003BF1.4090601@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linus Torvalds , "Eric W. Biederman" , Jeremy Fitzhardinge , Rusty Russell , David Miller , mingo@elte.hu, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, chrisw@sous-sol.org, anthony@codemonkey.ws, netdev@vger.kernel.org To: Zachary Amsden Return-path: Received: from colin.muc.de ([193.149.48.1]:2391 "EHLO mail.muc.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934044AbXCTUCo (ORCPT ); Tue, 20 Mar 2007 16:02:44 -0400 Date: Tue, 20 Mar 2007 21:02:42 +0100 Content-Disposition: inline In-Reply-To: <46003BF1.4090601@vmware.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > Worth it on 32-bit. On AMD64, probably not. On Intel 64-bit, maybe, > but less important than in P4 days. Well most of Intel 64bit is P4 -- and Intel is still shipping millions more of them each quarter. > This could change character completely if used at the tail of a function > where you now have > > sti; 1: ret > > Which generates an interrupt holdoff on the ret, an unusual thing to do. Unusual yes, but I don't see how it should cause problems. Or do you have anything specific in mind? Worse is probably that on K8 this case might cause a pipeline stall if there isn't a prefix in front of the ret. -Andi