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| author | Claudio Scordino <claudio@evidence.eu.com> | 2018-04-03 09:42:42 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-05-14 09:12:27 +0200 |
| commit | bb4e30a48045c9cc16c4efe447489542750397cc (patch) | |
| tree | 45438e51ce6e67a097fce532354011cec671e34f /Documentation/scheduler | |
| parent | 943d355d7feef380e15a95892be3dff1095ef54b (diff) | |
| download | lwn-bb4e30a48045c9cc16c4efe447489542750397cc.tar.gz lwn-bb4e30a48045c9cc16c4efe447489542750397cc.zip | |
sched/deadline/Documentation: Add overrun signal and GRUB-PA documentation
Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
Diffstat (limited to 'Documentation/scheduler')
| -rw-r--r-- | Documentation/scheduler/sched-deadline.txt | 25 |
1 files changed, 24 insertions, 1 deletions
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 |