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* sched/dl/Documentation: Split Section 3Luca Abeni2015-05-191-0/+16
| | | | | | | | | | | | | | | Introduce 4 subsections to make Section 3 more readable. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-10-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Clarify the relationship between tasks' deadlines ↵Luca Abeni2015-05-191-3/+11
| | | | | | | | | | | | | | | | | | | and absolute scheduling deadlines Clarify what is the relationship between tasks' parameters and scheduling parameters, explaining how to set the scheduling parameters so that all the absolute deadlines of a task are respected. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-9-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Add some referencesLuca Abeni2015-05-191-6/+67
| | | | | | | | | | | | | | | | | Add a description of the Dhall's effect, some discussion about schedulability tests for global EDF, and references to real-time literature. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-8-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Add some notes on EDF schedulabilityLuca Abeni2015-05-191-3/+42
| | | | | | | | | | | | | | | | | | | | | Add a short discussion about sufficient and necessary schedulability tests, and add a simple example showing that if D_i != P_i then density based tests are only sufficient. Also add some references to scientific papers on schedulability tests for EDF that are both necessary and sufficient, and on their computational complexity. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-7-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Clarify indexing notationLuca Abeni2015-05-191-5/+5
| | | | | | | | | | | | | | | | The "_i" index is used in this document to to denote a particular task, so "sum_i", "max_i" and "min_i" might be confusing. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-6-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Use consistent namingLuca Abeni2015-05-191-2/+2
| | | | | | | | | | | | | | | | The name "C_i" was used (without previously defining it) instead of "WCET_i". Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-5-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Fix typosLuca Abeni2015-05-191-2/+2
| | | | | | | | | | | | | Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-4-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Switch to American EnglishLuca Abeni2015-05-191-16/+16
| | | | | | | | | | | | | | | | This file previously mixed American and British English; switch to American for consistency. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-3-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/dl/Documentation: Correct the definition of density as C_i/min{D_i,P_i}Zhiqiang Zhang2015-05-191-2/+2
| | | | | | | | | | | | | | | | C_i/min{D_i,T_i}, where T_i is not referred before, should be substituted with C_i/min{D_i,P_i}. Signed-off-by: Zhiqiang Zhang <zhangzhiqiang.zhang@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: henrik@austad.us Cc: juri.lelli@gmail.com Cc: raistlin@linux.it Link: http://lkml.kernel.org/r/1431954032-16473-2-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Documentation/scheduler/sched-deadline.txt: Add minimal main() appendixJuri Lelli2014-09-161-0/+126
| | | | | | | | | | | | | | | | | Add an appendix providing a simple self-contained code snippet showing how SCHED_DEADLINE reservations can be created by application developers. Signed-off-by: Juri Lelli <juri.lelli@arm.com> Reviewed-by: Henrik Austad <henrik@austad.us> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1410256636-26171-6-git-send-email-juri.lelli@arm.com [ Fixed some whitespace inconsistencies. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Documentation/scheduler/sched-deadline.txt: Add tests suite appendixJuri Lelli2014-09-161-0/+52
| | | | | | | | | | | | | | | | Add an appendix briefly describing tools that can be used to test SCHED_DEADLINE (and the scheduler in general). Links to where source code of the tools is hosted are also provided. Signed-off-by: Juri Lelli <juri.lelli@arm.com> Reviewed-by: Henrik Austad <henrik@austad.us> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1410256636-26171-5-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Documentation/scheduler/sched-deadline.txt: Improve and clarify AC bitsLuca Abeni2014-09-161-17/+82
| | | | | | | | | | | | | | | | | | | | Admission control is of key importance for SCHED_DEADLINE, since it guarantees system schedulability (or tells us something about the degree of guarantees we can provide to the user). This patch improves and clarifies bits and pieces regarding AC, both for UP and SMP systems. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Juri Lelli <juri.lelli@arm.com> Reviewed-by: Henrik Austad <henrik@austad.us> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1410256636-26171-4-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Documentation/scheduler/sched-deadline.txt: Rewrite section 4 introJuri Lelli2014-09-161-26/+25
| | | | | | | | | | | | | | | | Section 4 intro was still describing the old interface. Rewrite it. Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Reviewed-by: Henrik Austad <henrik@austad.us> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1410256636-26171-3-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Documentation/scheduler/sched-deadline.txt: Fix terminology and improve clarityLuca Abeni2014-09-161-18/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | Several small changes regarding SCHED_DEADLINE documentation that fix terminology and improve clarity and readability: - "current runtime" becomes "remaining runtime" - readablity of an equation is improved by introducing more spacing - clarify when admission control will certainly fail - new URL for CBS technical report - substitue "smallest" with "earliest" Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Juri Lelli <juri.lelli@arm.com> Reviewed-by: Henrik Austad <henrik@austad.us> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1410256636-26171-2-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/deadline: Add sched_dl documentationDario Faggioli2014-01-281-0/+281
Add in Documentation/scheduler/ some hints about the design choices, the usage and the future possible developments of the sched_dl scheduling class and of the SCHED_DEADLINE policy. Reviewed-by: Henrik Austad <henrik@austad.us> Signed-off-by: Dario Faggioli <raistlin@linux.it> Signed-off-by: Juri Lelli <juri.lelli@gmail.com> [ Re-wrote sections 2 and 3. ] Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1390821615-23247-1-git-send-email-juri.lelli@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>