From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBDCEC6778A for ; Mon, 9 Jul 2018 10:48:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 98AFD20862 for ; Mon, 9 Jul 2018 10:48:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="RI6Rz+mJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 98AFD20862 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932699AbeGIKsF (ORCPT ); Mon, 9 Jul 2018 06:48:05 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:36638 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932278AbeGIKsE (ORCPT ); Mon, 9 Jul 2018 06:48:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=awv1x8h65NiTYcOVka/VNUxM6U7CJ1bsWXJ5bd7iHcI=; b=RI6Rz+mJwfyx+g/m0lAeXzaG0 qjXeDeokgXRdxCIZCapd6ViqsCsnvlz9fqRmIyu4I7Ng6MMhUSH32IOcYX3BBf8gJ4/IiorY+MdiR ym9i04P+Xl+ajZp8lJdxMV3wM2ljZVQu/2hchbh7xkdf4fiwZyFaH/5zQlEhqRp2SMEceAyiRv8zb ywUQbLbuRUZZAJWo80KmSBY+4ndh8EXvWyKePyy9f/klsvMPzbSjEwU1K/wbRd6N9A+NnXMcOSfCS GP6Wwgvlb8Zmki+S1/psggd3mGM3hbAW8qnhlUXcI3VHTVbb1ls522HceOmk7rbRzzofjTbpUCVBw 0S2lt9mkA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fcTi5-0003hP-C7; Mon, 09 Jul 2018 10:48:01 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D82E52029764D; Mon, 9 Jul 2018 12:47:59 +0200 (CEST) Date: Mon, 9 Jul 2018 12:47:59 +0200 From: Peter Zijlstra To: xunlei Cc: Xunlei Pang , Ingo Molnar , Frederic Weisbecker , Tejun Heo , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/cputime: Ensure correct utime and stime proportion Message-ID: <20180709104759.GJ2476@hirez.programming.kicks-ass.net> References: <20180622071542.61569-1-xlpang@linux.alibaba.com> <20180626154908.GE2458@hirez.programming.kicks-ass.net> <20180705104632.GE2494@hirez.programming.kicks-ass.net> <20180705134214.GF2494@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 05, 2018 at 09:58:50PM +0800, xunlei wrote: > It is rtime < utime + stime, that is the imprecise tick-based run time > may be larger than precise sum_exec_runtime scheduler-based run time, it > can happen with some frequent run-sleep patterns. You're still comparing two values that should not be compared. utime + stime is not a run-time. You _CANNOT_ compare to rtime and doing so means you're still not getting it.