[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] xen/arm: VCPU scheduling

On 20/12/2014 20:48, Vijay Kilari wrote:

Hi Vijay,

    I want to know what is the criteria followed in Xen for scheduling VCPUs.
Assume below scenario:

  - Run 2 VPCUs on 1 Physical CPU
  - VCPUs does not trap on WFE or WFE ( either by WFI/WFE trap is
disabled in HCR OR no WFE/WFI in EL1 is executed).

In such scenario, does Xen assumes that VCPU0 is always running because it has
NOT trapped on WFI and WFE (not yielded voluntary) and does not
schedule VCPU1? or is it time shared?

The scheduler allocates time slice to each VCPU. Once the slice is ending, another VCPU may be scheduled.

Xen is also trapping WFE/WFI to allow better performance. Why would you want to disable WFE/WFI traps?


Julien Grall

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.