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 AC1DAC388F7 for ; Tue, 3 Nov 2020 22:10:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 739C92080D for ; Tue, 3 Nov 2020 22:10:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="kSOrZCkd"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="0XFyqK39" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731648AbgKCWKL (ORCPT ); Tue, 3 Nov 2020 17:10:11 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:45012 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729764AbgKCWKJ (ORCPT ); Tue, 3 Nov 2020 17:10:09 -0500 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1604441407; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=8fYu6MuaJ0Ok/Y49A6p/r2wWyaAYSztubvJXZfAJjx8=; b=kSOrZCkd+5bm3VUzBCKp+nXf6Jm7gHJqEst/8Y8Y7kCKavfTO6EsO6Fbfu5IWFm7Yh0rOh ViOh1ai4o5f0PzkGC6gnQU0hccQS3A0dsAu6zIpTriXCVe8LYJKI0b83pLLX4BemllgEQ6 +IQR9J0bMajTKl5Wq0d2SPBn9SWwC3qrE+PB++4G0G8IfyOx9BoLgfM6EkEutRo8WTxhwq MlO0X8D6Jsn2qbEWzgvUE1Zb1jqzlTRrYhfELhwbbtuWglFP6/4tTy4CG7I7hp5vG+2T3N IPrsCMkaOm0iBHMsLlRmPUmfvf6Gy5W+vaq7iru3s8Ka7+yMQ3SgEgROjA8WHw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1604441407; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=8fYu6MuaJ0Ok/Y49A6p/r2wWyaAYSztubvJXZfAJjx8=; b=0XFyqK39HcF4/ENuNbZFJU0QS3/l+9z7UfPcGscjnLvY1kuRMumepPSyYBcqHw+YIi3h5E hih5bXfXsCTgC8Cw== To: Sudeep Holla , Elliot Berman Cc: Qais Yousef , Peter Zijlstra , "Paul E. McKenney" , Jonathan Corbet , Sudeep Holla , Trilok Soni , linux-kernel@vger.kernel.org, psodagud@codeaurora.org, linux-doc@vger.kernel.org Subject: Re: [PATCH] smp: Add bootcpus parameter to boot subset of CPUs In-Reply-To: <20201030174531.ywwkcntq4ge33lrh@bogus> References: <1603404243-5536-1-git-send-email-eberman@codeaurora.org> <87v9f04n8r.fsf@nanos.tec.linutronix.de> <20201026171224.GV2611@hirez.programming.kicks-ass.net> <20201028145516.23lm66mora5b3wqr@e107158-lin> <20201028151558.odxwolnwbes2gihi@bogus> <20201030174531.ywwkcntq4ge33lrh@bogus> Date: Tue, 03 Nov 2020 23:10:06 +0100 Message-ID: <871rha148x.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, Oct 30 2020 at 17:45, Sudeep Holla wrote: > On Thu, Oct 29, 2020 at 02:37:06PM -0700, Elliot Berman wrote: >> In the case where commercial device is using feature for thermal, device >> should boot multiple small cores. Booting only one core means we would not >> be able to use all possible cores to maximum extent possible in this thermal >> case. > > I understood that point. But you haven't responded on my logical vs physical > number argument. I am clearly NACKing this patch as is for just usage of > logical CPU IDs in the command line while your intention is to control > the physical CPUs. So once again, NACK for that reason. Correct. And no, we are not going to add a command line option to select physical CPU ids. There are two ways to solve that: 1) The firmware can tell the kernel whether a CPU should be brought up or not, e.g. by failing the bootup request. 2) The kernel has a way to figure out the current thermal and/or power budget early in the boot process and sorts out which and how many CPUs fit into that limit. Thanks, tglx