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=-5.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 19CDFC004C9 for ; Tue, 7 May 2019 14:31:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA4692087F for ; Tue, 7 May 2019 14:31:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726795AbfEGObc (ORCPT ); Tue, 7 May 2019 10:31:32 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:56028 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726403AbfEGObc (ORCPT ); Tue, 7 May 2019 10:31:32 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AE06680D; Tue, 7 May 2019 07:31:31 -0700 (PDT) Received: from queper01-lin (queper01-lin.cambridge.arm.com [10.1.195.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2ECE73F5C1; Tue, 7 May 2019 07:31:29 -0700 (PDT) Date: Tue, 7 May 2019 15:31:27 +0100 From: Quentin Perret To: luca abeni Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , "Rafael J . Wysocki" , Ingo Molnar , Peter Zijlstra , Vincent Guittot , "Paul E . McKenney" , Joel Fernandes , Luc Van Oostenryck , Morten Rasmussen , Juri Lelli , Daniel Bristot de Oliveira , Patrick Bellasi , Tommaso Cucinotta Subject: Re: [RFC PATCH 1/6] sched/dl: Improve deadline admission control for asymmetric CPU capacities Message-ID: <20190507143125.cjfhdxngcugqmko3@queper01-lin> References: <20190506044836.2914-1-luca.abeni@santannapisa.it> <20190506044836.2914-2-luca.abeni@santannapisa.it> <20190507134850.yreebscc3zigfmtd@queper01-lin> <20190507162523.6a405d48@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190507162523.6a405d48@nowhere> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 07 May 2019 at 16:25:23 (+0200), luca abeni wrote: > On Tue, 7 May 2019 14:48:52 +0100 > Quentin Perret wrote: > > > Hi Luca, > > > > On Monday 06 May 2019 at 06:48:31 (+0200), Luca Abeni wrote: > > > diff --git a/drivers/base/arch_topology.c > > > b/drivers/base/arch_topology.c index edfcf8d982e4..646d6d349d53 > > > 100644 --- a/drivers/base/arch_topology.c > > > +++ b/drivers/base/arch_topology.c > > > @@ -36,6 +36,7 @@ DEFINE_PER_CPU(unsigned long, cpu_scale) = > > > SCHED_CAPACITY_SCALE; > > > void topology_set_cpu_scale(unsigned int cpu, unsigned long > > > capacity) { > > > + topology_update_cpu_capacity(cpu, per_cpu(cpu_scale, cpu), > > > capacity); > > > > Why is that one needed ? Don't you end up re-building the sched > > domains after this anyways ? > > If I remember correctly, this function was called at boot time when the > capacities are assigned to the CPU cores. > > I do not remember if the sched domain was re-built after this call, but > I admit I do not know this part of the kernel very well... Right and things moved recently in this area, see bb1fbdd3c3fd ("sched/topology, drivers/base/arch_topology: Rebuild the sched_domain hierarchy when capacities change") > This achieved the effect of correctly setting up the "rd_capacity" > field, but I do not know if there is a better/simpler way to achieve > the same result :) OK, that's really an implementation detail, so no need to worry too much about it at the RFC stage I suppose :-) Thanks, Quentin