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From: Julien Grall <julien.grall@arm.com>
To: Suriyan Ramasami <suriyan.r@gmail.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	"Ivan Pavić2" <Ivan.Pavic2@fer.hr>
Subject: Re: Odroid XU3 support
Date: Thu, 28 Apr 2016 10:50:33 +0100	[thread overview]
Message-ID: <5721DCE9.1020904@arm.com> (raw)
In-Reply-To: <CANoR_ODOjJyHsxsXhpnzMM9A4MqLsoWzSu+LGJz=CLdsxoAYLQ@mail.gmail.com>

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.

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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  reply	other threads:[~2016-04-28  9:50 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-25 10:01 Odroid XU3 support Ivan Pavić2
2016-04-26 10:31 ` Julien Grall
2016-04-27 22:53   ` Suriyan Ramasami
2016-04-28  9:50     ` Julien Grall [this message]
2016-04-28 13:19       ` Ivan Pavić2
2016-04-28 13:26       ` Suriyan Ramasami
2016-05-05 11:39         ` Julien Grall
2016-05-05 11:39           ` Julien Grall
2016-05-08 11:59       ` Peng Fan
2016-05-09  9:49         ` Julien Grall
2016-05-10  7:53           ` Peng Fan
2016-05-10  9:33             ` Julien Grall

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