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

yodaiken@fsmlabs.com
Tue, 30 Jan 2001 13:51:54 -0700


> 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

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/