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 2ACF1C6778A for ; Thu, 5 Jul 2018 10:46:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C514521E5B for ; Thu, 5 Jul 2018 10:46:43 +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="M9ZfXESJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C514521E5B 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 S1753602AbeGEKql (ORCPT ); Thu, 5 Jul 2018 06:46:41 -0400 Received: from merlin.infradead.org ([205.233.59.134]:40812 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753290AbeGEKqj (ORCPT ); Thu, 5 Jul 2018 06:46:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=PNTZhAcVkB/spv/5lMF9sMGHbhKVUojN9hVVdja50F4=; b=M9ZfXESJGJJxSOQEzqrr14Bie cXNh5/m8MqdAbsUQ4zYefASWclxZdovN0vqCJNxrcCox4nBrcMhJf0hcSy6aQwq8jYfR6OktP70Uc +U8016W9ijq5EahbK3hkRtlFRzPXkjzmYa8SQkeOe3DAvPQqrf42RCjlzty0lOTmWVaMTnJ/yqRlD dLkw3y0SAmlruGveX2vI/TAVGZhKifRmgmIGKg84o4ZcO8F5EhHtyt4Dvz53XSxGu5ycwfzaMkFTw vkqBgI94LjFRO7KYLF0a7mB8fHZHVnjxUZ7WJ0ISqr1eJOfsQbPDeQiePCf1Z0gGLz/f4XJos35v4 j184ulwqg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fb1mV-0005tc-6s; Thu, 05 Jul 2018 10:46:35 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9745F20289CB2; Thu, 5 Jul 2018 12:46:32 +0200 (CEST) Date: Thu, 5 Jul 2018 12:46:32 +0200 From: Peter Zijlstra To: Xunlei Pang Cc: Ingo Molnar , Frederic Weisbecker , Tejun Heo , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/cputime: Ensure correct utime and stime proportion Message-ID: <20180705104632.GE2494@hirez.programming.kicks-ass.net> References: <20180622071542.61569-1-xlpang@linux.alibaba.com> <20180626154908.GE2458@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 Wed, Jun 27, 2018 at 08:22:42PM +0800, Xunlei Pang wrote: > tick-based whole utime is utime_0, tick-based whole stime > is stime_0, scheduler time is rtime_0. > For a long time, the process runs mainly in userspace with > run-sleep patterns, and because two different clocks, it > is possible to have the following condition: > rtime_0 < utime_0 (as with little stime_0) I don't follow... what? Why are you, and why do you think it makes sense to, compare rtime_0 against utime_0 ? The [us]time_0 are, per your earlier definition, ticks. They're not an actual measure of time. Do not compare the two, that makes no bloody sense.