From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760402Ab0JGOt6 (ORCPT ); Thu, 7 Oct 2010 10:49:58 -0400 Received: from terminus.zytor.com ([198.137.202.10]:42842 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758023Ab0JGOt5 (ORCPT ); Thu, 7 Oct 2010 10:49:57 -0400 Message-ID: <4CADDD9F.3030806@zytor.com> Date: Thu, 07 Oct 2010 07:47:59 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc13 Thunderbird/3.1.4 MIME-Version: 1.0 To: Stephane Eranian CC: mingo@elte.hu, Hans.Rosenfeld@amd.com, robert.richter@amd.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, Andreas.Herrmann3@amd.com, peterz@infradead.org, fweisbec@gmail.com, rostedt@goodmis.org, acme@redhat.com, Peter Zijlstra , eranian@gmail.com Subject: Re: [RFC 0/3] Basic support for LWP References: <1286212172-654419-1-git-send-email-hans.rosenfeld@amd.com> <20101005145155.GD173@escobedo.osrc.amd.com> <20101005182739.GE173@escobedo.osrc.amd.com> <20101005190501.GA21916@elte.hu> <20101006073558.GJ13563@erda.amd.com> <4CADD257.7080203@zytor.com> <4CADD73B.8070809@zytor.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/07/2010 07:25 AM, Stephane Eranian wrote: >> >> No, but you wouldn't be able to use lazy FPU. >> > You mean lazy restore, I am guessing here. > Is that to say, you cannot figure out whether the FPU state in > the CPU on ctxsw in is yours anymore? > Lazy save/restore, and more or less, yes. Really, XSAVE was designed to be saved/restored as a unit, with unused state skipped. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.