sched deadline - elinux.org · 2016-07-06 · sched_deadline numbers* frame rate = 23.9 fps ift =...
TRANSCRIPT
![Page 2: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/2.jpg)
2
AgendaPresentation outline
Deadline scheduling (AKA SCHED_DEADLINE) What is it?
Status update
Under discussionBandwidth reclaiming
Clock frequency selection hints
Future workGroup scheduling
Dynamic feedback mechanism
Enhanced priority inheritance
Energy awareness
![Page 3: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/3.jpg)
3
AgendaPresentation outline
Deadline scheduling (AKA SCHED_DEADLINE) What is it?
Status update
Under discussionBandwidth reclaiming
Clock frequency selection hints
Future workGroup scheduling
Dynamic feedback mechanism
Enhanced priority inheritance
Energy awareness
![Page 4: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/4.jpg)
4
SCHED_DEADLINEWhat is it?
it's not only about deadlines relatively new addition to the Linux scheduler
since v3.14
real-time scheduling policyhigher priority than NORMAL and FIFO/RR
only root can use it (for now …)
enables predictable task schedulingallows explicit per-task latency constraints
avoids starvation (tasks cannot eat all available CPU time)
enriches scheduler's knowledge about QoS requirements
![Page 5: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/5.jpg)
5
SCHED_DEADLINEWhat is it?
Predictability and Isolation
SCHED_NORMALdefault Linux scheduling policy
SCHED_DEADLINE finer-grained control over tasks scheduling tasks don't interfere with each other
4 CPU-hog processes on 4 CPUs
![Page 6: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/6.jpg)
6
SCHED_DEADLINEWhat is it?
Linux scheduler classes and policies
Linux scheduler
fair.crt.cdeadline.c
SCHED_DEADLINESCHED_DEADLINE
SCHED_RRSCHED_RR
SCHED_BATCHSCHED_BATCH
SCHED_IDLESCHED_IDLE
SCHED_NORMALSCHED_NORMAL
SCHED_FIFOSCHED_FIFO
![Page 7: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/7.jpg)
7
SCHED_DEADLINEEDF + CBS
it implements Earlies Deadline First (EDF)
tasks with earliest deadline get executed first
Constant Bandwidth Server (CBS)reservation based scheduling
it's the cool thing here!
![Page 8: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/8.jpg)
8
SCHED_DEADLINEEDF (plain)
τ1 5 time units every 9→ ~89% utilization
τ2 2 time units every 6→
τ1
τ2
t
t
![Page 9: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/9.jpg)
9
SCHED_DEADLINEEDF (plain: problems)
τ1 second job behaves bad→
τ1 causes a deadline miss on τ2
τ1
τ2
t
t
![Page 10: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/10.jpg)
10
SCHED_DEADLINEEDF (plain: problems)
τ1 blocks just after the second activation→
τ1 resumes with the third instance of → τ2
τ1
τ2
t
t
τ1 causes a deadline miss on τ2
![Page 11: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/11.jpg)
11
SCHED_DEADLINEConstant Bandwidth Server (and EDF)
resource (CPU) reservation mechanisma task is allowed to execute for
Q time units (runtime)
in every interval of length P (period)
CBS computes reservation's dynamic deadlinesslowing down or throttling misbehaving tasks
EDF gives higher priority to more urgent reservations EDF + CBS provides temporal isolation
![Page 12: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/12.jpg)
12
SCHED_DEADLINEEDF + CBS
plain EDF
(bad task) →
τ1 second job behaves bad→
τ1 once budget exhausted, delay until next period →
τ1
τ2
t
t
τ1
τ2
t
t
![Page 13: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/13.jpg)
13
SCHED_DEADLINEEDF + CBS
plain EDF
(block/unblock) →
τ1
τ2
t
t
τ1 blocks just after the second activation→
τ1 resumes with the third instance of → τ2
CBS “unblock rule” applied
τ1
τ2
t
t
![Page 14: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/14.jpg)
14
SCHED_DEADLINELoad Balancing and Inheritance (and a question)
active load balancing (push/pull)like for SCHED_FIFO
global EDF: on an M-CPUs system the M earliest DL ready tasks are always running (respecting affinity/cpusets)
deadline inheritanceboosted task inherits deadline of the donor
suboptimal solution… see future work
common question: does it work with PREEMPT_RT ?it's orthogonal to it
PREEMPT_RT reduces latencies, SCHED_DEADLINE implements a scheduling algorithm (can benefit from the former)
they should work together without any problem :-)
![Page 15: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/15.jpg)
15
SCHED_DEADLINEhow to setup params
simple rule of thumb
runtime [ns]
deadline [ns]
period [ns]
average
activation deadline next activation
![Page 16: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/16.jpg)
16
SCHED_DEADLINEAPIstruct sched_attr {
u32 size;
u32 sched_policy;
u64 sched_flags;
/* SCHED_NORMAL, SCHED_BATCH */
s32 sched_nice;
/* SCHED_FIFO, SCHED_RR */
u32 sched_priority;
/* SCHED_DEADLINE */
u64 sched_runtime;
u64 sched_deadline;
u64 sched_period;
};
int sched_setattr(pid_t pid, const struct sched_attr *attr, unsigned int flags);
int sched_getattr(pid_t pid, const struct sched_attr *attr, unsigned int size, unsigned int flags);
runtime [ns]
deadline [ns]
period [ns]
average
![Page 17: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/17.jpg)
17
SCHED_DEADLINEExample of usage
#include <sched.h>...
struct sched_attr attr;
attr.size = sizeof(struct attr);
attr.sched_policy = SCHED_DEADLINE;
attr.sched_runtime = 30000000;
attr.sched_period = 100000000;
attr.sched_deadline = attr.sched_period;
...
if (sched_setattr(gettid(), &attr, 0))
perror("sched_setattr()");
...
![Page 18: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/18.jpg)
18
SCHED_DEADLINEnumbers*
mplayer HD movie QoS is inter-frame time
(IFT)curr_dt – prev_dt
Variation in IFT is bad 6 other instances of
mplayer in background
frame rate = 23.9 fpsIFT = 41708 us
* Juri Lelli, Claudio Scordino, Luca Abeni, Dario Faggioli, Deadline scheduling in the Linux kernel, Software: Practice and Experience 2015 http://onlinelibrary.wiley.com/doi/10.1002/spe.2335/abstract
cumulative distribution function (CDF)vertical line at expected IFT gives best result
![Page 19: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/19.jpg)
19
SCHED_DEADLINEnumbers*
frame rate = 23.9 fpsIFT = 41708 us
SCHED_NORMAL (CFS)QoS highly dependent onsystem load
* Juri Lelli, Claudio Scordino, Luca Abeni, Dario Faggioli, Deadline scheduling in the Linux kernel, Software: Practice and Experience 2015 http://onlinelibrary.wiley.com/doi/10.1002/spe.2335/abstract
![Page 20: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/20.jpg)
20
SCHED_DEADLINEnumbers*
frame rate = 23.9 fpsIFT = 41708 us
SCHED_NORMAL (CFS)QoS highly dependent onsystem load
SCHED_DEADLINEplayer not affected(period = IFT , runtime = 13ms)
* Juri Lelli, Claudio Scordino, Luca Abeni, Dario Faggioli, Deadline scheduling in the Linux kernel, Software: Practice and Experience 2015 http://onlinelibrary.wiley.com/doi/10.1002/spe.2335/abstract
![Page 21: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/21.jpg)
21
AgendaPresentation outline
Deadline scheduling (AKA SCHED_DEADLINE) What is it?
Status update
Under discussionBandwidth reclaiming
Clock frequency selection hints
Future workGroup scheduling
Dynamic feedback mechanism
Enhanced priority inheritance
Energy awareness
![Page 22: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/22.jpg)
22
Bandwidth reclaimingunder discussion*
* CPU reclaiming for SCHED_DEADLINE https://lwn.net/Articles/671929/
tasks' bandwidth is fixedcan only be changed with syscall
what if tasks occasionally need more bandwidth ?occasional workload fluctuations (e.g., network traffic, rendering particularly heavy frame)
reclaiming: allow tasks to consume more than allocatedup to a certain maximum fraction of CPU time
if this doesn't break others' guarantees
implementation detailsgreedy reclaiming of unused bandwidth (GRUB)
Luca Abeni (University of Trento) driving this
![Page 23: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/23.jpg)
23
Bandwidth reclaimingresults*
* Luca Abeni, Juri Lelli, Claudio Scordino, Luigi Palopoli, Greedy CPU reclaiming for SCHED_DEADLINE, RTLWS14 http://disi.unitn.it/~abeni/reclaiming/rtlws14-grub.pdf
Task1 (6ms, 20ms)constant execution time (5ms)
Task2 (45ms, 260ms)experiences occasional variances (35-52ms)
T2 reservation period
CD
F
Response time (ms)
![Page 24: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/24.jpg)
24
Bandwidth reclaimingresults*
Task1 (6ms, 20ms)constant execution time (5ms)
Task2 (45ms, 260ms)experiences occasional variances (35-52ms)
T2 reservation period
Plain CBST2 response time bigger than reservation period (~25%)
CD
F
Response time (ms)
* Luca Abeni, Juri Lelli, Claudio Scordino, Luigi Palopoli, Greedy CPU reclaiming for SCHED_DEADLINE, RTLWS14 http://disi.unitn.it/~abeni/reclaiming/rtlws14-grub.pdf
![Page 25: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/25.jpg)
25
Bandwidth reclaimingresults*
Task1 (6ms, 20ms)constant execution time (5ms)
Task2 (45ms, 260ms)experiences occasional variances (35-52ms)
Response time (ms)
T2 reservation period
CD
FGRUBT2 always completes before reservation period (using time left by T1)
* Luca Abeni, Juri Lelli, Claudio Scordino, Luigi Palopoli, Greedy CPU reclaiming for SCHED_DEADLINE, RTLWS14 http://disi.unitn.it/~abeni/reclaiming/rtlws14-grub.pdf
![Page 26: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/26.jpg)
26
Clock frequency selection hintsunder discussion*
* https://lkml.org/lkml/2016/3/17/420 https://lkml.org/lkml/2016/2/22/1037
scheduler driven CPU clock frequency selectionschedfreq/schedutil solutions
each scheduling class has to provide hints
admitted bandwidth trackingworst case utilization
“ghost” utilization
bandwidth reclaiming introduces per CPU active utilization tracking
better indication tasks' actual requirements
instead of donating we can decide to clock down, saving energy
![Page 27: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/27.jpg)
27
AgendaPresentation outline
Deadline scheduling (AKA SCHED_DEADLINE) What is it?
Status update
Under discussionBandwidth reclaiming
Clock frequency selection hints
Future workGroup scheduling
Dynamic feedback mechanism
Enhanced priority inheritance
Energy awareness
![Page 28: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/28.jpg)
28
Group schedulingfuture work
one to one association between tasks and reservations sometime is better/easier to group a set of tasks under
the same umbrellavirtual machine threads
rendering pipeline
implement cgroups support (like for NORMAL/FIFO)theory needs thinking: how can we guarantee isolation between local and global scheduler ?
once done it might replace FIFO/RR throttling
might be a practical solution for forking question
![Page 29: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/29.jpg)
29
Dynamic feedback mechanismfuture work
choosing reservation parameters can be difficult (tradeoff)
a runtime too small ends up affecting QoS
a runtime too big ends up wasting CPU resource
runtime feedback mechanism to adapt reservations to varying workloads
bigger time scales than bandwidth reclaiming
needs collaboration between kernel and userspace
middleware or runtime (e.g., Android) is probably best placed
![Page 30: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/30.jpg)
30
Enhanced priority inheritancefuture work
move from deadline inheritance to … bandwidth inheritance similar to proxy scheduling boosted task runs into the donor's reservation not extremely easy on multiprocessors :-/
![Page 31: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/31.jpg)
31
Energy awarenessfuture work
in the context of energy aware scheduling (EAS*) meet QoS requirements in the most energy efficient way several things needs changing
introduce capacity and power awareness
start using energy model
make balancing decisions energy aware
better integration of scheduling decisions across scheduling policies is probably required
* https://lkml.org/lkml/2015/7/7/754
![Page 32: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/32.jpg)
32
Conclusions
Kernel space has already quite some features and more is in the pipeline, but…
we need more userspace adoption to foster further development (or at least more people telling us they are using it :-))
![Page 33: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/33.jpg)
33
Conclusions
Kernel space has already quite some features and more is in the pipeline, but…
we need more userspace adoption to foster further development (or at least more people telling us they are using it :-))
![Page 34: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/34.jpg)
34
Conclusions
Kernel space has already quite some features and more is in the pipeline, but…
we need more userspace adoption to foster further development (or at least more people telling us they are using it :-))
![Page 35: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/35.jpg)
35
Conclusions
Kernel space has already quite some features and more is in the pipeline, but…
we need more userspace adoption to foster further development (or at least more people telling us they are using it :-))
![Page 36: SCHED DEADLINE - eLinux.org · 2016-07-06 · SCHED_DEADLINE numbers* frame rate = 23.9 fps IFT = 41708 us SCHED_NORMAL (CFS) QoS highly dependent on system load SCHED_DEADLINE player](https://reader035.vdocuments.net/reader035/viewer/2022070719/5eded273ad6a402d666a2cbe/html5/thumbnails/36.jpg)
The Architecture for the Digital World®
Thank You!
Juri [email protected]
The trademarks featured in this presentation are registered and/or unregistered trademarks of ARM limited (or its subsidiaries) in the EUand/or elsewhere. All rights reserved. All other marks featured may be trademarks of their respective owners.