Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752628AbaLSLYI (ORCPT ); Fri, 19 Dec 2014 06:24:08 -0500 Received: from casper.infradead.org ([85.118.1.10]:43286 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752357AbaLSLYG (ORCPT ); Fri, 19 Dec 2014 06:24:06 -0500 Date: Fri, 19 Dec 2014 12:23:50 +0100 From: Peter Zijlstra To: Andy Lutomirski Cc: Shaohua Li , "linux-kernel@vger.kernel.org" , X86 ML , Kernel-team@fb.com, "H. Peter Anvin" , Ingo Molnar , John Stultz Subject: Re: [PATCH v2 3/3] X86: Add a thread cpu time implementation to vDSO Message-ID: <20141219112350.GJ30905@twins.programming.kicks-ass.net> References: <8559794d3a1924408a811a2881ab916fffb6015b.1418857018.git.shli@fb.com> <95a7ba1a95a6251439d5ca2d3d56fe7f0778cb95.1418857018.git.shli@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 18, 2014 at 04:22:59PM -0800, Andy Lutomirski wrote: > Bad news: this patch is incorrect, I think. Take a look at > update_rq_clock -- it does fancy things involving irq time and > paravirt steal time. So this patch could result in extremely > non-monotonic results. Yeah, I'm not sure how (and if) we could make all that work :/ -- 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/