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=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, 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 ED781C55178 for ; Wed, 21 Oct 2020 13:10:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7FFDC22275 for ; Wed, 21 Oct 2020 13:10:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="XOXAe90u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2442864AbgJUNKk (ORCPT ); Wed, 21 Oct 2020 09:10:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2441234AbgJUNKk (ORCPT ); Wed, 21 Oct 2020 09:10:40 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B132C0613CE; Wed, 21 Oct 2020 06:10:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=eMjOkbUQtyeR5+wl3KwNKG0mBA6u1w78Ht1qDvj8EUs=; b=XOXAe90uOp2gPvsCtG0tTg6Ao2 2XE+Ty8fPaU5r8eefEGKM/d/kBOGs3aUCs8LYwORcbVoW1b8Dtnl1HHo9PLGTCzQGXEBPMm3sCniL muoYuTAyWDtqv2Pv5D7UYrlWZD1k2VbpR1OFJ5Y5k2lWPHbRXZeDfP5dhW/QNdF/PYdN+nSMLmSye ftr45RvGKireghJ+iRVF86cYnqAxMot8bOw6e0wLmbdV/PwQTDgbSqYxFwAnhHNoB4JI1nTdVwiyl oRNPumatQYa+h5FCA7LgQftkyJ1T5y7x+qK3hGFD+WKTQATkgXM2+yAaqkXz+SEqDv3vWQrDIeJyS k4zHdhbw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kVDsp-0008Nx-DF; Wed, 21 Oct 2020 13:10:27 +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 B3F15304D2B; Wed, 21 Oct 2020 15:10:26 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 7F5E22140541A; Wed, 21 Oct 2020 15:10:26 +0200 (CEST) Date: Wed, 21 Oct 2020 15:10:26 +0200 From: Peter Zijlstra To: Julia Lawall Cc: Mel Gorman , Ingo Molnar , kernel-janitors@vger.kernel.org, Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Daniel Bristot de Oliveira , linux-kernel@vger.kernel.org, Valentin Schneider , Gilles Muller , "Rafael J. Wysocki" , viresh.kumar@linaro.org, srinivas.pandruvada@linux.intel.com Subject: Re: [PATCH] sched/fair: check for idle core Message-ID: <20201021131026.GY2651@hirez.programming.kicks-ass.net> References: <1603211879-1064-1-git-send-email-Julia.Lawall@inria.fr> <20201021112038.GC32041@suse.de> <20201021121950.GF2628@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201021121950.GF2628@hirez.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 21, 2020 at 02:19:50PM +0200, Peter Zijlstra wrote: > On Wed, Oct 21, 2020 at 01:56:55PM +0200, Julia Lawall wrote: > > Prior to 5.8, my machine was using intel_pstate and had few background > > tasks. Thus the problem wasn't visible in practice. Starting with 5.8 > > the kernel decided that intel_cpufreq would be more appropriate, which > > introduced kworkers every 0.004 seconds on all cores. > > That still doesn't make any sense. Are you running the legacy on-demand > thing or something? > > Rafael, Srinivas, Viresh, how come it defaults to that? Does we want something like this? --- arch/x86/configs/i386_defconfig | 3 +-- arch/x86/configs/x86_64_defconfig | 3 +-- drivers/cpufreq/Kconfig | 7 +++++-- 3 files changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig index 78210793d357..c343ad459737 100644 --- a/arch/x86/configs/i386_defconfig +++ b/arch/x86/configs/i386_defconfig @@ -41,8 +41,7 @@ CONFIG_PM_DEBUG=y CONFIG_PM_TRACE_RTC=y CONFIG_ACPI_DOCK=y CONFIG_ACPI_BGRT=y -CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y -CONFIG_CPU_FREQ_GOV_ONDEMAND=y +CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL=y CONFIG_X86_ACPI_CPUFREQ=y CONFIG_EFI_VARS=y CONFIG_KPROBES=y diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig index 9936528e1939..23e1ea85c1ec 100644 --- a/arch/x86/configs/x86_64_defconfig +++ b/arch/x86/configs/x86_64_defconfig @@ -38,8 +38,7 @@ CONFIG_PM_DEBUG=y CONFIG_PM_TRACE_RTC=y CONFIG_ACPI_DOCK=y CONFIG_ACPI_BGRT=y -CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y -CONFIG_CPU_FREQ_GOV_ONDEMAND=y +CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL=y CONFIG_X86_ACPI_CPUFREQ=y CONFIG_IA32_EMULATION=y CONFIG_EFI_VARS=y diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index 2c7171e0b001..8dfca6e9b836 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -37,8 +37,7 @@ config CPU_FREQ_STAT choice prompt "Default CPUFreq governor" default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ - default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if ARM64 || ARM - default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP + default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if SMP default CPU_FREQ_DEFAULT_GOV_PERFORMANCE help This option sets which CPUFreq governor shall be loaded at @@ -71,6 +70,7 @@ config CPU_FREQ_DEFAULT_GOV_USERSPACE config CPU_FREQ_DEFAULT_GOV_ONDEMAND bool "ondemand" + depends on !SMP select CPU_FREQ_GOV_ONDEMAND select CPU_FREQ_GOV_PERFORMANCE help @@ -83,6 +83,7 @@ config CPU_FREQ_DEFAULT_GOV_ONDEMAND config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE bool "conservative" + depends on !SMP select CPU_FREQ_GOV_CONSERVATIVE select CPU_FREQ_GOV_PERFORMANCE help @@ -144,6 +145,7 @@ config CPU_FREQ_GOV_USERSPACE config CPU_FREQ_GOV_ONDEMAND tristate "'ondemand' cpufreq policy governor" + depends on !SMP select CPU_FREQ_GOV_COMMON help 'ondemand' - This driver adds a dynamic cpufreq policy governor. @@ -163,6 +165,7 @@ config CPU_FREQ_GOV_ONDEMAND config CPU_FREQ_GOV_CONSERVATIVE tristate "'conservative' cpufreq governor" depends on CPU_FREQ + depends on !SMP select CPU_FREQ_GOV_COMMON help 'conservative' - this driver is rather similar to the 'ondemand'