Messages in this thread | | | Date | Tue, 13 Jan 2009 11:44:52 +0200 | From | Jussi Laako <> | Subject | Re: [RFC][PATCH] Multimedia scheduling class |
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Peter Zijlstra wrote: > > Well, that's not my problem is it ;-), just batter them with a > clue-stick, no need to fudge the kernel for that.
Sure, been doing that already... :) There's just sort of a huge gap between rt-schedulers and the normal scheduler.
> Right, which is where deadline scheduling would be nice. Once you start > running into the budget throttle you know you've got to start dropping > frames in order to keep up. > > The proposal is for it to start sending SIGXCPU once it starts > throttling tasks in order to notify them of missed deadlines etc.
For sure this is nice for certain tasks. I'm not entirely convinced if the average media player or Flash-plugin would or should start using these.
I believe both approaches could co-exist to address different needs. SCHED_MM is for the average software and is in a sense similar to SCHED_BATCH and SCHED_IDLE, just targeting different use cases. Modification is reasonably small and shouldn't have any impact when not used. Deadline scheduler would probably belong to the SCHED_RR/SCHED_FIFO family?
> Like said, deadline schedulers can help here. You can even dynamically > adjust the parameters -- eg. fall back to half frame rate but double > budget or something.
Managing the budget in an average system will be painful. In a completely embedded environment this is of course rather straightforward.
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