From patchwork Tue May 23 08:53:43 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juri Lelli X-Patchwork-Id: 100363 Delivered-To: patch@linaro.org Received: by 10.140.96.100 with SMTP id j91csp218612qge; Tue, 23 May 2017 01:59:30 -0700 (PDT) X-Received: by 10.84.241.206 with SMTP id t14mr34999308plm.48.1495529970827; Tue, 23 May 2017 01:59:30 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1495529970; cv=none; d=google.com; s=arc-20160816; b=jYjJgj2bOOUVJlvCcgZDn+KXTmdttCXKJAiJRN/XM2/mybL38PpWVDC4hucWncYiQy xwBbw7bRZRhvuHKWd1Puv+zzLMvfVphdza5x/h/Gwdlz7dTvSs1YExhsRjCU6KODW0jy uqVQdKHbcFUfNeQX/fuubY2QM68JuHuMx3y5DL8SDbvF1rUarcmqhmC+egY7yDIJxGw0 eKYZZip6WtT9++DKAgc3E/DaFa4JjvhGOjK14Z4aevboixgI7xgaLf4cp6gnVKJzo1BW ACmXB3vFgcJMuyhQSVONuEIMTeBECsVqxv8RXLBkwK669gRBxGlyYL2gGI703ddgYYBP xw+A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:message-id:date:subject:cc:to:from :arc-authentication-results; bh=f7oafhuzbKUYMkc1+9jdpBrGQFJLN6h/dDYmHYa4uyE=; b=Toay6Bfg7/F/H8Tu2UY3jS8pYpN6RdkuAYC5OAOBJtiBoM76LvKZbQ9uZHqIz+DXl8 2MT2+VEnQl1uhCEqONbP/FxcS3/VhXowTuAbNFODUY656tKqppOOtixUmX9KJlzoN2mO Ol3wWVMj0MDekQHWyzi+HiAex9tqCcF3374NZrRvCGEyGFSrPdpT2GgM9ghvrw9hM/tr KbyDXdqp9SSiKxNNYK1OFnSMKDlYfdSE662W+/rnab6DqTkUl6XkhXN23jsC6ary8E6I x3DrV4+fP2+olG+iYu0DDnh2hvJ9iXIN/QTrFXAmrcPBsVlC+WFFXPtc+qZOLm2yCgc9 2trQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id r7si20382783pli.26.2017.05.23.01.59.30; Tue, 23 May 2017 01:59:30 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967146AbdEWI7D (ORCPT + 25 others); Tue, 23 May 2017 04:59:03 -0400 Received: from foss.arm.com ([217.140.101.70]:48044 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936672AbdEWIyc (ORCPT ); Tue, 23 May 2017 04:54:32 -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 5D9C9344; Tue, 23 May 2017 01:54:26 -0700 (PDT) Received: from cam-smtp0.cambridge.arm.com (e106622-lin.cambridge.arm.com [10.1.211.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 0DA9B3F53D; Tue, 23 May 2017 01:54:22 -0700 (PDT) From: Juri Lelli To: peterz@infradead.org, mingo@redhat.com, rjw@rjwysocki.net, viresh.kumar@linaro.org Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, tglx@linutronix.de, vincent.guittot@linaro.org, rostedt@goodmis.org, luca.abeni@santannapisa.it, claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it, bristot@redhat.com, mathieu.poirier@linaro.org, tkjos@android.com, joelaf@google.com, andresoportus@google.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, patrick.bellasi@arm.com, juri.lelli@arm.com Subject: [PATCH RFC 0/8] SCHED_DEADLINE freq/cpu invariance and OPP selection Date: Tue, 23 May 2017 09:53:43 +0100 Message-Id: <20170523085351.18586-1-juri.lelli@arm.com> X-Mailer: git-send-email 2.11.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, this RFC set implements frequency/cpu invariance and OPP selection for SCHED_DEADLINE. The set has been slightly tested on a Juno platform. The current incarnation of the patches stems both from previous RFD[1] review comments and discussion at OSPM-summit[2], during which we seemed to agree that: - we probably want to use running_bw (instead of this_bw), as it is less pessimistic (we should save more energy) - special kworker hack seems acceptable as a mid term solution to foster further SCHED_DEADLINE/schedutil development/adoption A point that is still very much up for discussion (more that the others :) is how we implement frequency/cpu scaling. SCHED_FLAG_RECLAIM tasks only need grub_reclaim(), as the function already scales their reservation runtime considering other reservations and maximum bandwidth a CPU has to offer. However, for normal !RECLAIM tasks multiple things can be implemented which seem to make sense: - don't scale at all: normal tasks will only get a % of CPU _time_ as granted by AC - go to max as soon as a normal task in enqueued: this because dimensioning of parameters is usually done at max OPP/biggest CPU and normal task assume that this is always the condition when they run - scale runtime acconding to current frequency and max CPU capacity: this is what this set is currently implementing Opinions? The set is based on tip/sched/core as of today (a9e7f6544b9c) plus some schedutil fixes coming from linux-pm/linux-next and Luca's "CPU reclaiming for SCHED_DEADLINE" [3]. Patches high level description: o [01-02]/08 add the necessary links to start accounting DEADLINE contribution to OPP selection o 03/08 it's a temporary solution to make possible (on ARM) to change frequency for DEADLINE tasks (that would possibly delay the SCHED_FIFO worker kthread); proper solution would be to be able to issue frequency transition from an atomic ctx o [04-05]/08 it's a schedutil change that copes with the fact that DEADLINE doesn't require periodic OPP selection triggering point o [06-07]/08 make arch_scale_{freq,cpu}_capacity() function available on !CONFIG_SMP configurations too o 08/08 implements frequency/cpu invariance for tasks' reservation parameters; which basically means that we implement GRUB-PA [4] Changes w.r.t. RFD: - use grub_reclaim for RECLAIM and scale freq/cpu for !RECLAIM - discard CFS contribution only, after TICK_NSEC - added patches 06 and 07 to fix !CONFIG_SMP builds Please have a look. Feedback and comments are, as usual, more than welcome. In case you would like to test this out: git://linux-arm.org/linux-jl.git upstream/deadline/freq-rfc Best, - Juri [1] http://marc.info/?l=linux-kernel&m=149036457909119&w=2 [2] http://retis.sssup.it/ospm-summit/program.html https://lwn.net/Articles/721573/ [3] http://marc.info/?l=linux-kernel&m=149513848804404 [4] C. Scordino, G. Lipari, A Resource Reservation Algorithm for Power-Aware Scheduling of Periodic and Aperiodic Real-Time Tasks, IEEE Transactions on Computers, December 2006. Juri Lelli (8): sched/cpufreq_schedutil: make use of DEADLINE utilization signal sched/deadline: move cpu frequency selection triggering points sched/cpufreq_schedutil: make worker kthread be SCHED_DEADLINE sched/cpufreq_schedutil: split utilization signals sched/cpufreq_schedutil: always consider all CPUs when deciding next freq sched/sched.h: remove sd arch_scale_freq_capacity parameter sched/sched.h: move arch_scale_{freq,cpu}_capacity outside CONFIG_SMP sched/deadline: make bandwidth enforcement scale-invariant include/linux/sched.h | 1 + include/linux/sched/cpufreq.h | 2 -- include/linux/sched/topology.h | 12 ++++---- include/uapi/linux/sched.h | 1 + kernel/sched/core.c | 19 ++++++++++-- kernel/sched/cpufreq_schedutil.c | 62 ++++++++++++++++++++++++---------------- kernel/sched/deadline.c | 39 ++++++++++++++++++++----- kernel/sched/fair.c | 4 +-- kernel/sched/sched.h | 27 +++++++++++++---- 9 files changed, 116 insertions(+), 51 deletions(-) -- 2.11.0