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_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 61AAFC433DF for ; Wed, 3 Jun 2020 19:59:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41AC52074B for ; Wed, 3 Jun 2020 19:59:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="Wh/2nlbR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726088AbgFCT7E (ORCPT ); Wed, 3 Jun 2020 15:59:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725922AbgFCT7E (ORCPT ); Wed, 3 Jun 2020 15:59:04 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AFDABC08C5C0 for ; Wed, 3 Jun 2020 12:59:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: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=tg8mNhsE0qlps5ciALLkNONY+9bvqdzo03558zZho/4=; b=Wh/2nlbRDwoeC9J0ac3xyk/Jk zQty8vNNDayaTgr5QL1Xvauoyc93BcKurh2nK51uQqfprOqyUVUfoXXIOgnlFizlapzncHwENxKAp 48NUwyvSWDRNdpi/K/7btTTyXaEmO/CVluzeLa1uYicu0Qg/S7tJqOevW0d+S3jky8khAgqAhAARe It3hNKj7C5OahkvOvhB1SXbhV6dqZZyM4KeKmXAbIbIh0Bb4S0gNeY27dUSvqw8TNp6WmhMtXPEKD 2u7VQX77SBjmniwTjflfdwgnLUhW5/aw+JmNV4kp6QNUC3RtgrK73RAM/lOSnJ+DceYynFWPNj1zB dOiWsf49A==; Received: from shell.armlinux.org.uk ([2001:4d48:ad52:3201:5054:ff:fe00:4ec]:48984) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jgZXM-0006E7-IL; Wed, 03 Jun 2020 20:58:56 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jgZXJ-0005fr-Uq; Wed, 03 Jun 2020 20:58:53 +0100 Date: Wed, 3 Jun 2020 20:58:53 +0100 From: Russell King - ARM Linux admin To: Vincent Guittot Cc: Valentin Schneider , Thara Gopinath , linux-kernel Subject: Re: v5.7: new core kernel option missing help text Message-ID: <20200603195853.GD1551@shell.armlinux.org.uk> References: <20200603173150.GB1551@shell.armlinux.org.uk> <20200603184500.GC1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 03, 2020 at 09:24:56PM +0200, Vincent Guittot wrote: > On Wed, 3 Jun 2020 at 20:45, Russell King - ARM Linux admin > wrote: > > It's a start. I'm still wondering whether I should answer yes or no > > for the platforms I'm building for. > > > > So far, all I've found is: > > > > arch/arm/include/asm/topology.h:#define arch_scale_thermal_pressure topology_get_thermal_pressure > > > > which really doesn't tell me anything about this. So I'm still in > > the dark. > > > > I guess topology_get_thermal_pressure is provided by something in > > drivers/ which will be conditional on some driver or something. > > You need cpufreq_cooling device to make it useful and only for SMP > I don't think that this should not be user configurable because even > with the description above, it is not easy to choose. > This should be set by the driver that implement the feature which is > only cpufreq cooling device for now it As I have CONFIG_CPU_FREQ_THERMAL=y in my config, I'm guessing (and it's only a guess) that I should say y to SCHED_THERMAL_PRESSURE ? > > > + help > > > + This option allows the scheduler to be aware of CPU thermal throttling > > > + (i.e. thermal pressure), providing arch_scale_thermal_pressure() is > > > + implemented. Is this feature documented in terms of what it does? Do I assume that as the thermal trip points start tripping, that has an influence on the scheduler? Or is it the case that the scheduler is wanting to know when the cpu frequency changes? Grepping for "thermal" in Documentation/scheduler brings up nothing. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up