Re: [linux-audio-dev] low-latency scheduling patch for 2.4.0

yodaiken
2001-01-30T20:52:36Z

> The thing that really does concern me about the flash driver code is the
> fact that it often wants to wait for about 100µs. On machines with
> HZ==100, that sucks if you use udelay() and it sucks if you schedule(). So
> we end up dropping the spinlock (so at least bottom halves can run again)
> and calling:
>
> static inline void cfi_udelay(int us)
> {
> if (current->need_resched)
> schedule();
> else
> udelay(us);
> }

So then a >100us delay is ok ?

I have a dumb RT perspective: either you have to make the deadline or you don't.
If you have to make the deadline, then why are you checking need_resched?

--
---------------------------------------------------------
Victor Yodaiken
Finite State Machine Labs: The RTLinux Company.
www.fsmlabs.com www.rtlinux.com