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SubjectRe: Can't sleep less than 20 ms
Rogier Wolff wrote:
> IA32 should also use HZ=1000. However, the API (now cast in stone)
> specifies that HZ == 100 when seen from userland. Linus has suggested
> that the kernel-HZ need not be the same as what is "published" to the
> user applications.

HZ == 1000 looks like yet another arbitrary decision. Why is 1000Hz
good enough yet 100Hz is not?

x86 also takes 10 or more microseconds to service an interrupt (it is
said because of motherboards not the CPU itself).

Do you really want to spend 1% CPU servicing timer interrupts just so
_occasionally_ a program can get a short sleep to 2ms accuracy?

I'd rather see:

- slow HZ -- low interrupt load
- accurate timers on demand
- *precise* timing with accuracy of hardware

[ And then I'd like to see the accurate timers used for polling network
cards under load :-) ]


-- Jamie

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