Re: a joint letter on low latency and Linux

[Bill Huey]

> At one extreme we've been looking at providing a mechanism similar to what
> RTAI gives programmers.  We can make your program look like it's running in
> a normal pthreads environment without the RTLinux API as long as you stick
> to some constraints such as not doing file IO and other things incompatible
> with realtime (things you're not likely to do in time critical code
> anyway).

Cort,

Yeah, that looks pretty good for a DSP chains that need tighter than
soft-realtime support like effect processing. But the question of
audio/media stuff is often a hybrid of many things within the kernel
(tight timing of data movement, etc..) and outside of it (TCP/IP,
explicit scheduling of raw disk data, VM scanning wierdness, etc...).

So this stuff is good for a certain sizeable set of the problem, but
ultimately you need to have low latency in for user space stuff too.

Doing various kinds of heavy disk IO shouldn't effect how the machine
does math computations. It's silly otherwise.

I'll take a look at it what you've guy have done recently with the API. :-)

Thanks

bill