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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 877AAC64EBC for ; Wed, 3 Oct 2018 09:01:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 57A44213A2 for ; Wed, 3 Oct 2018 09:01:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 57A44213A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rjwysocki.net 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 S1727694AbeJCPsr (ORCPT ); Wed, 3 Oct 2018 11:48:47 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:51575 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727188AbeJCPsr (ORCPT ); Wed, 3 Oct 2018 11:48:47 -0400 Received: from 79.184.253.194.ipv4.supernova.orange.pl (79.184.253.194) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.148) id b640457e59a45be6; Wed, 3 Oct 2018 11:01:17 +0200 From: "Rafael J. Wysocki" To: Daniel Lezcano , "Peter Zijlstra (Intel)" Cc: linux-pm@vger.kernel.org, Todd Kjos , Joel Fernandes , Colin Cross , Ramesh Thomas , Alex Shi , LKML Subject: Re: [PATCH RFC] cpuidle/drivers/menu: Remove get_loadavg in the performance multiplier Date: Wed, 03 Oct 2018 10:58:16 +0200 Message-ID: <4200780.ZjVhNjpZ67@aspire.rjw.lan> In-Reply-To: <1537868328-13405-1-git-send-email-daniel.lezcano@linaro.org> References: <1537868328-13405-1-git-send-email-daniel.lezcano@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, September 25, 2018 11:38:44 AM CEST Daniel Lezcano wrote: > The function get_loadavg() returns almost always zero. To be more > precise, statistically speaking for a total of 1023379 times passing > to the function, the load is equal to zero 1020728 times, greater than > 100, 610 times, the remaining is between 0 and 5. > > I'm putting in question this metric. Is it worth to keep it? The honest answer is that I'm not sure. Using the CPU load for driving idle state selection is questionable in general (there need not be any connection between the two in principle) and this particular function is questionable either. If it really makes no difference in addition to that, then yes it would be good to get rid of it. That said it looks like that may be quite workload-dependent, so maybe there are workloads where it does make a difference? Like networking or similar? Thanks, Rafael