Hello Julien,
Thank you for the advice. I do have a follow up question.
On Thu, Apr 28, 2016 at 2:50 AM, Julien Grall <julien.gr...@arm.com> wrote:
> Hello,
>
> On 27/04/16 23:53, Suriyan Ramasami wrote:
>
> How can I check which core is currently active?
>> Judging by this link on big.LITTLE architecture:
>> http://forum.odroid.com/viewtopic.php?f=65&t=2580
>>
>> result of: cat /proc/cpuinfo | grep "CPU part" is
>> CPU part : 0xc07
>>
>> which stands for A7.
>>
>> If you do this in dom0, it will show all of them to be 0xc07. They are
>> vCPUs after all.
>>
>
> Which is not a good idea. This means that Linux is not able to detect
> potential errata for the underlying cores (in this case the cortex-A15).
> Also some userspace may do some runtime optimization based on the kind of
> CPUs available in the guest.
>
> Xen is not ready for big.LITTLE, so I would highly recommend you to
> disable either all the Cortex-A15 or Cortex-A7.
>
>
Ian did recommend that if they were in their own cpu pools it would avoid
mixing them in a guest. I was researching that angle. What is your take on
that?
If Linux is not recognizing it, that is a dom0/domU issue, is it not?
Nonetheless, to start with, to add support, I think there would be less
resistance if the boot cluster (a7) cpus are enabled and the other cluster
disabled (a15)
For your information, I am planning to send a patch to park any CPUs whose
> MIDR is not matching the boot CPU one.
>
> Regards,
>
> --
> Julien Grall
>
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