Re: [Xen-devel] Problems with enabling hypervisor C and P-statecontrol

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 25/10/08 04:01, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote:

>> We really ought to have code in Xen to make the enumeration consistent
>> regardless of the BIOS order. I don't really care whether its
>> sockets/cores/threads or threads/cores/sockets, but we really ought to
>> be consistent.
> 
> If Xen wants to be consistent with one policy, as you suggested, it
> requires core/thread info known before booting APs, and then take
> that info in alloc_cpu_id. However core/thread info can be only
> acquired on AP by CPUID and sibling/core map can be constructed
> after all APs are booted.

Sort by LAPIC ID. The LAPIC ID is defined to be hierarchical, so this would
automatically get us sorting by thread then core then socket. This could be
as simple as arranging for the calls to mp_register_lapic() to happen in the
correct order.

> Then you may need a temporary cpu id
> allocated and then switch it to a real one later. This looks a bit
> messed on some arrays[NR_CPUS]. Is it worthy of doing that way,
> or just expose the mapping between xen cpu id and sockets/cores/
> threads?

The mapping between flat identifier and socket/core/thread should be made
available, and/or modify tools to accept a hierarchical cpu identifier in
addition to the old-style flat identifier.

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel