Re: [Qemu-arm] [Qemu-devel] [PATCH v7 01/16] hw/cpu: introduce CPU clusters

[Luc Michel]

On 12/4/18 7:24 PM, Peter Maydell wrote:
> On Tue, 4 Dec 2018 at 18:06, Eduardo Habkost <address@hidden> wrote:
>> In either case, I'm still missing a clear description of what a
>> cluster is supposed to represent, exactly (see my previous reply
>> on this thread).
> 
> Here's my attempt:
> 
> A cluster is a group of CPUs which are all identical and have
> the same view of the rest of the system.
> If CPUs are not identical (for example, Cortex-A53 and
> Cortex-A57 CPUs in an Arm big.LITTLE system) they should be
> in different clusters.
> If the CPUs do not have the same view of memory (for example
> the main CPU and a management controller processor) they should
> be in different clusters.
Thanks, I'll use that as a start point for the documentation in cluster.h

-- 
Luc

> 
> I agree that this is slightly confusing, because the concept
> is on the boundary between something that's real in hardware
> (eg in a big.LITTLE setup the CPUs are in separate hardware
> clusters, and of coures a BMC processor and the main CPU
> are definitely different things) and something that we're
> defining for its effects on the GDB UI and so we can make
> sure we don't share TCG translated code where we shouldn't.
> 
> thanks
> -- PMM
>