Re: Bad MIDI performance : 10ms latency instead of the expected

Jaroslav Kysela (perex@suse.cz)
Thu, 26 Aug 1999 22:51:18 +0200 (MEST)


On Thu, 26 Aug 1999, Alan Cox wrote:

> > > 200bytes/sec is just rudiculous , how do you plan to drive an external synth
> > > with that little MIDI bandwidth ?
> >
> > I need a timer around 2000Hz for some good code. I won't support polling
> > mode (busy loop) in any case.
>
> Then your code will never be usable. Some hardware sucks, you have to do
> limited polling with a timer backoff. A well tuned polling loop will often
> work out nicely providing you are careful. Remember with irqs on you are
> just like busy in userspace no worse. You can even do
>
> while(poll_input()==0)
> {
> if(current->need_resched())
> schedule();
> }
>
> sort of stuff

Is possible to create some thread for this loop inside kernel module?
I don't want to suspend the application execution due to a broken
hardware. I did some tests with 2.2 kernels (using kernel_thread()) and
I've not been successful.

Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
SuSE Linux http://www.suse.com
ALSA project http://www.alsa-project.org

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