Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt

Andi Kleen
2005-07-15T17:59:07Z

> I wouldn't say it is totally impossible. There are ways in which Linux can work
> without a reliable Local APIC timer. One option being - make one CPU that gets
> the external timer interrupt multicast an IPI to all the other CPUs that
> wants to get periodic timer interrupt.

That doesn't mix very well with variable ticks. And I believe
we really need them.

For no tick in idle you need a timer for each CPU that
can be programmed to a reasonably long interval to wake you
up after longer idleness. And all that
should work without bouncing cache lines around all the time
because that doesn't work on larger systems.

-Andi