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RE: [Xen-devel] [PATCH] Make HZ a boot-time configurable

> In addition the scheduler is set up to send the *current* 
> guest a periodic ticker at 100HZ. This last value is 
> hardcoded in xen/common/schedule.c. again this timer is run 
> off the local APIC.
> Arguably, the frequency for this ticker should be settable 
> per guest to reflect its HZ value (or equivalent).

Or done away with altogether...

As I recall, the complication with doing this is that we don't want
periodic timer interrupts to wake the domain up when its otherwise not
running (whether due to having been preempted or being blocked).

At a minimum, we need to make the ticker freq programmable on a
per-domain basis (including '0Hz'). 

Alternatively, we introduce a new event notification function that only
actually 'kicks' the domain if its already runnning.

Which option is preferred? I'd like to see this make the 3.0-testing
cut, though I guess option 1 could be done in a hypervisor-API backward
compatible fashion.

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