Re: nanosleep() for shorted than schedule slice

[mlelstv%serpens.de@localhost (Michael van Elst)]

bqt%softjar.se@localhost (Johnny Billquist) writes:

>> A tickless kernel wouldn't run callouts from the regular clock interrupt
>> but would use a hires timer to issue interrupts at arbitrary times.
>> The callout API could then be changed to either accept timespec values or
>> just fake a much higher HZ value.

>Right. Not that I believe this have to be tied into tickless, but I 
>suspect it might be easier to do it if we go tickless.


Well, "not using a regular clock interrupt" is what "tickless" means.


>We really should be able to deal with shorter times, even if we have 
>ticks.

That's a contradiction. "ticks" means that timed events are based
on a regular clock interrupt. Of course you can speed up the ticks
(e.g. Alpha uses HZ=1000), but that has other disadvantages.

N.B. going tickless isn't difficult, it's just lots of work as it needs
MD support on all platforms.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."