Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965598AbXBFXvG (ORCPT ); Tue, 6 Feb 2007 18:51:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965600AbXBFXvG (ORCPT ); Tue, 6 Feb 2007 18:51:06 -0500 Received: from smtp-outbound-1.vmware.com ([65.113.40.141]:45035 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S965598AbXBFXuz (ORCPT ); Tue, 6 Feb 2007 18:50:55 -0500 Message-ID: <45C9145E.7080800@vmware.com> Date: Tue, 06 Feb 2007 15:50:54 -0800 From: Zachary Amsden User-Agent: Thunderbird 1.5.0.9 (X11/20061206) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Andi Kleen , Linux Kernel Mailing List , Andrew Morton , Rusty Russell , Chris Wright Subject: Re: [PATCH 2/11] Sched clock paravirt op References: <200702060352.l163qeAf000727@zach-dev.vmware.com> <20070206123256.GF47229@muc.de> <45C9056A.8060504@vmware.com> <45C90DDA.3060009@goop.org> <45C9125A.3040704@vmware.com> <45C913B6.4080701@goop.org> In-Reply-To: <45C913B6.4080701@goop.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1321 Lines: 37 Jeremy Fitzhardinge wrote: > Zachary Amsden wrote: > >> Jeremy Fitzhardinge wrote: >> >>> Zachary Amsden wrote: >>> >>> >>>> Scheduled (or available) time and real time are good notions. Stolen >>>> time is debatable. But TSC is basically just always wrong. That's >>>> why I don't want to overload the rdtsc operation. >>>> >>> Well, in the Xen case it is actually guaranteed to be correct and useful >>> as real time, but that's definitely not something we can expect in >>> general. But you're talking specifically about schedulable vcpu time >>> here, right? >>> >>> >> Not schedulable time, scheduled time (schedulable - scheduled) = stolen >> > > I meant "schedulable" (perhaps "usable" would be better) from the > guest's perspective: total amount of real cpu time each vcpu gets. ie: > (real - schedulable) = stolen. So I think we're talking about the same > thing. > Yes, I think so. The point though, is the for Xen, TSC is real time. So it won't do for the scheduler, which must be schedulable time. Zach - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/