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=-0.8 required=3.0 tests=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 BADA9C2D0EA for ; Wed, 8 Apr 2020 10:42:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8895020771 for ; Wed, 8 Apr 2020 10:42:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728154AbgDHKmX (ORCPT ); Wed, 8 Apr 2020 06:42:23 -0400 Received: from foss.arm.com ([217.140.110.172]:36774 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726734AbgDHKmX (ORCPT ); Wed, 8 Apr 2020 06:42:23 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 75D7931B; Wed, 8 Apr 2020 03:42:22 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 745523F73D; Wed, 8 Apr 2020 03:42:20 -0700 (PDT) References: <20200408095012.3819-1-dietmar.eggemann@arm.com> <20200408095012.3819-3-dietmar.eggemann@arm.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Dietmar Eggemann Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Luca Abeni , Daniel Bristot de Oliveira , Wei Wang , Quentin Perret , Alessio Balsini , Pavan Kondeti , Patrick Bellasi , Morten Rasmussen , Qais Yousef , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] sched/deadline: Improve admission control for asymmetric CPU capacities Message-ID: In-reply-to: <20200408095012.3819-3-dietmar.eggemann@arm.com> Date: Wed, 08 Apr 2020 11:42:14 +0100 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/04/20 10:50, Dietmar Eggemann wrote: > +++ b/kernel/sched/sched.h > @@ -304,11 +304,14 @@ void __dl_add(struct dl_bw *dl_b, u64 tsk_bw, int cpus) > __dl_update(dl_b, -((s32)tsk_bw / cpus)); > } > > +static inline unsigned long rd_capacity(int cpu); > + > static inline > -bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw) > +bool __dl_overflow(struct dl_bw *dl_b, int cpu, u64 old_bw, u64 new_bw) > { > return dl_b->bw != -1 && > - dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw; > + cap_scale(dl_b->bw, rd_capacity(cpu)) < > + dl_b->total_bw - old_bw + new_bw; > } > I don't think this is strictly equivalent to what we have now for the SMP case. 'cpus' used to come from dl_bw_cpus(), which is an ugly way of writing cpumask_weight(rd->span AND cpu_active_mask); The rd->cpu_capacity_orig field you added gets set once per domain rebuild, so it also happens in sched_cpu_(de)activate() but is separate from touching cpu_active_mask. AFAICT this mean we can observe a CPU as !active but still see its capacity_orig accounted in a root_domain. > extern void init_dl_bw(struct dl_bw *dl_b);