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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 DB4BFC433E7 for ; Mon, 12 Oct 2020 11:21:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 636402076E for ; Mon, 12 Oct 2020 11:21:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="e8lgh9G9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388135AbgJLLVi (ORCPT ); Mon, 12 Oct 2020 07:21:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387992AbgJLLVh (ORCPT ); Mon, 12 Oct 2020 07:21:37 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC8C4C0613CE for ; Mon, 12 Oct 2020 04:21:37 -0700 (PDT) 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; bh=/2aTZMV+2S4NyMORmTfPJ7G20RSywvvEejTMHJJTKvU=; b=e8lgh9G9EYf39tvYlcs2jYDCZ9 6DgKjdDcFZesLpoKDn0UE+pVYS9vryG1SXdAHOaSw3oS4x+a0VtLYpeis8r0EQsEn8TM32FoSWz9d +QcJeh4sS4tYpirJ+v2/+wRSpWK6YHmVRIh3X+8EtPMrbGqJ0FW1ooZZhGy+z5ibxj/4rcqE1G8z7 Clcadjuu5Kc3PUEQ5rxZRg5Hp+pPnrNMnrNDD8hYlsU5YLXkef4dTWhPp7aE2eaChM2XLgW0itOSo 7GLAvm/Dp0bUvkry5riz6ToqY57mmumulXEMMNwLsMiGR/9fuVTITb7sAEiLYL3kv0CHCB4gYweKb HqMeSfcQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kRvtP-0006XN-PJ; Mon, 12 Oct 2020 11:21:27 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id B8D09304B90; Mon, 12 Oct 2020 13:21:24 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9A2D920116727; Mon, 12 Oct 2020 13:21:24 +0200 (CEST) Date: Mon, 12 Oct 2020 13:21:24 +0200 From: Peter Zijlstra To: Julia Lawall Cc: Valentin Schneider , Ingo Molnar , Juri Lelli , Vincent Guittot , linux-kernel@vger.kernel.org, Gilles Muller , "Rafael J. Wysocki" Subject: Re: SD_LOAD_BALANCE Message-ID: <20201012112124.GT2628@hirez.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 10, 2020 at 06:14:23PM +0200, Julia Lawall wrote: > Prior to v5.8 on my machine this was a rare event, because there were not > many of these background processes. But in v5.8, the default governor for > Intel machines without the HWP feature was changed from intel_pstate to > intel_cpufreq. The use of intel_cpufreq triggers very frequent kworkers on > all cores, which makes it much more likely that cores that are currently > idle, and are overall not at all overloaded, will have a higher load > average even with the waking thread deducted, than the core managing the > wakeup of the threads. Rafael, any idea what those kworkers are for, and can we get rid of them?