Re: Scheduler fixes

Michael O'Reilly (michael@metal.iinet.net.au)
25 Jun 1998 13:50:46 +0800


MOLNAR Ingo <mingo@valerie.inf.elte.hu> writes:
>
> btw, we could do _exact_ process accounting if we want to, at the price of
> ~10-15 cycles per schedule(). we can just read the cycle counter (industry
> standard on most leading CPUs ;), add the delta to the process and do the
> math later, whenever someone (top) tries to access the values. This way we
> could even differentiate between IRQ cycles, kernel cycles, kernel thread
> cycles, idle cycles and user-space cycles. Is this an important and
> fundamental enough feature to justify those 10-15 cycles?

IMHO, yes, definately. The people that care about the 10-15 cycles are
the ones most likely to care about the inaccurate counters... :)

How often is schedule() called anyway? Even if it's 1000 times per
second, you're talking much less than 0.1% of cpu time.

Michael.

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