Re: [RFC][PATCH] Multimedia scheduling class

From: James Courtier-Dutton
Date: Sat Jan 17 2009 - 08:11:51 EST


Jussi Laako wrote:
> 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.
>

There is never a need for media players to use this.
Media players have time stamps on the displayed frames.
If the timestamp on a frame indicates it has taken too long to decode
it, the media player just skips the frame until it reaches frames that
have non-expired time stamps. No need for any kernel help here.

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