Re: [RFC][PATCH] Multimedia scheduling class

[Jussi Laako <jussi@sonarnerd.net>]

Jussi Laako wrote:
> Yes, this is for a soft-realtime usage. Some of the tasks are
> CPU-intensive while being realtime'ish, like video codecs and some audio
> processing tasks. These audio processing tasks can have some amount of
> buffering. The idea behind this patch is to make these tasks overlap
> with the normal tasks while giving a slightly more responsive scheduling
> behavior and to favor these multimedia tasks over others.

I've been running a kernel with the scheduler patch on my x86-64 desktop
since Christmas.

Here are some test results... Workload in these tests is mostly starting
a browser and rendering a set of reasonably heavy pages which creates
CPU load spikes. BKL is a bit of a problem too...

I think this is reasonably good result.


Results for the deskop (x86-64), voluntary preempt enabled (as the
proprietary ATI display driver behaves badly with full preempt):

SCHED_OTHER:
maximum latency: 45098.2 µs
average latency: 366.2 µs
missed timer events: 16

SCHED_MM:
maximum latency: 10051.2 µs
average latency: 44.7 µs
missed timer events: 0

SCHED_FIFO:
maximum latency: 720.3 µs
average latency: 23.1 µs
missed timer events: 0


Results for an OMAP3-based platform, preempt enabled:

SCHED_OTHER:
maximum latency: 44.7 ms
average latency: 1.8 ms
missed timer events: 227

SCHED_MM:
maximum latency: 19.2 ms
average latency: 1.1 ms
missed timer events: 23

SCHED_FIFO:
maximum latency: 10.7 ms
average latency: 0.7 ms
missed timer events: 1


Best regards,

	- Jussi Laako