Messages in this thread | | | Date | Fri, 15 Jul 2005 11:09:21 -0700 | From | Venkatesh Pallipadi <> | Subject | Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt |
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On Fri, Jul 15, 2005 at 07:57:01PM +0200, Andi Kleen wrote: > > 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.
It should work with variable ticks as we can easily add/remove CPUs from this multicast destination.
> 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.
And each CPU timer itself does very little writes in terms of caches. The two things that happen here are scheduler_tick and kstat_accounting. Or am I missing something? Did you have anything specific in mind wrt bouncing cachelines?
Thanks, Venki
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