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Re: [Xen-devel] Credit scheduler
30msec is the maximum time slice.
And I guess your 3 microsecond is the response after
SCHEDULE_SOFTIRQ is set.
As you know,
If SCHEDULE_SOFTIRQ is set,
it waits softirq calls schedule(). (this time interval is 3microsec)
And I/O intensive has higher priority than CPU intensive.
So I/O intensive job is first dispatched domain in runq.
This is because latency improvement for I/O intensive guest.
So your behavior is not strange.
> I have noticed that VMs are typically spending 3 microsecs or less before
> they are being prempted. I thought that the credit schduler time slice was 30
> ms. I have 4 VMs running and they are all cpu intensive except for 1 (which
> is IO intensive) but having a VM spend max 3 micro secs before being kicked
> out seems strange.
> Is there something else going on that i am not aware of. Is the time slice
> really 30 millisecs? I am using default parameters of the credit scheduler.
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