From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752483AbeENHxn (ORCPT ); Mon, 14 May 2018 03:53:43 -0400 Received: from terminus.zytor.com ([198.137.202.136]:45035 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752081AbeENHxi (ORCPT ); Mon, 14 May 2018 03:53:38 -0400 Date: Mon, 14 May 2018 00:53:02 -0700 From: tip-bot for Claudio Scordino Message-ID: Cc: hpa@zytor.com, juri.lelli@redhat.com, corbet@lwn.net, mingo@kernel.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, peterz@infradead.org, efault@gmx.de, claudio@evidence.eu.com, luca.abeni@santannapisa.it, tglx@linutronix.de Reply-To: efault@gmx.de, peterz@infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, luca.abeni@santannapisa.it, claudio@evidence.eu.com, mingo@kernel.org, corbet@lwn.net, juri.lelli@redhat.com, hpa@zytor.com, torvalds@linux-foundation.org In-Reply-To: <1522741362-4542-1-git-send-email-claudio@evidence.eu.com> References: <1522741362-4542-1-git-send-email-claudio@evidence.eu.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/deadline/Documentation: Add overrun signal and GRUB-PA documentation Git-Commit-ID: bb4e30a48045c9cc16c4efe447489542750397cc X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bb4e30a48045c9cc16c4efe447489542750397cc Gitweb: https://git.kernel.org/tip/bb4e30a48045c9cc16c4efe447489542750397cc Author: Claudio Scordino AuthorDate: Tue, 3 Apr 2018 09:42:42 +0200 Committer: Ingo Molnar CommitDate: Mon, 14 May 2018 09:12:27 +0200 sched/deadline/Documentation: Add overrun signal and GRUB-PA documentation Signed-off-by: Claudio Scordino Signed-off-by: Peter Zijlstra (Intel) Cc: Jonathan Corbet Cc: Juri Lelli Cc: Linus Torvalds Cc: Luca Abeni Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1522741362-4542-1-git-send-email-claudio@evidence.eu.com Signed-off-by: Ingo Molnar --- Documentation/scheduler/sched-deadline.txt | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/Documentation/scheduler/sched-deadline.txt b/Documentation/scheduler/sched-deadline.txt index 8ce78f82ae23..b14e03ff3528 100644 --- a/Documentation/scheduler/sched-deadline.txt +++ b/Documentation/scheduler/sched-deadline.txt @@ -49,7 +49,7 @@ CONTENTS 2.1 Main algorithm ------------------ - SCHED_DEADLINE uses three parameters, named "runtime", "period", and + SCHED_DEADLINE [18] uses three parameters, named "runtime", "period", and "deadline", to schedule tasks. A SCHED_DEADLINE task should receive "runtime" microseconds of execution time every "period" microseconds, and these "runtime" microseconds are available within "deadline" microseconds @@ -117,6 +117,10 @@ CONTENTS scheduling deadline = scheduling deadline + period remaining runtime = remaining runtime + runtime + The SCHED_FLAG_DL_OVERRUN flag in sched_attr's sched_flags field allows a task + to get informed about runtime overruns through the delivery of SIGXCPU + signals. + 2.2 Bandwidth reclaiming ------------------------ @@ -279,6 +283,19 @@ CONTENTS running_bw is incremented. +2.3 Energy-aware scheduling +------------------------ + + When cpufreq's schedutil governor is selected, SCHED_DEADLINE implements the + GRUB-PA [19] algorithm, reducing the CPU operating frequency to the minimum + value that still allows to meet the deadlines. This behavior is currently + implemented only for ARM architectures. + + A particular care must be taken in case the time needed for changing frequency + is of the same order of magnitude of the reservation period. In such cases, + setting a fixed CPU frequency results in a lower amount of deadline misses. + + 3. Scheduling Real-Time Tasks ============================= @@ -505,6 +522,12 @@ CONTENTS 17 - L. Abeni, G. Lipari, A. Parri, Y. Sun, Multicore CPU reclaiming: parallel or sequential?. In Proceedings of the 31st Annual ACM Symposium on Applied Computing, 2016. + 18 - J. Lelli, C. Scordino, L. Abeni, D. Faggioli, Deadline scheduling in the + Linux kernel, Software: Practice and Experience, 46(6): 821-839, June + 2016. + 19 - C. Scordino, L. Abeni, J. Lelli, Energy-Aware Real-Time Scheduling in + the Linux Kernel, 33rd ACM/SIGAPP Symposium On Applied Computing (SAC + 2018), Pau, France, April 2018. 4. Bandwidth management