Re: [Qemu-devel] [PATCH v7 01/13] machine: Don't allow CPU toplogies with partially filled cores

[David Gibson]

On Thu, Jan 28, 2016 at 11:19:43AM +0530, Bharata B Rao wrote:
> Prevent guests from booting with CPU topologies that have partially
> filled CPU cores or can result in partially filled CPU cores after
> CPU hotplug like
> 
> -smp 15,sockets=1,cores=4,threads=4,maxcpus=16 or
> -smp 15,sockets=1,cores=4,threads=4,maxcpus=17.
> 
> This is enforced by introducing MachineClass::validate_smp_config()
> that gets called from generic SMP parsing code. Machine type versions
> that want to enforce this can define this to the generic version
> provided.
> 
> Only sPAPR and PC machine types starting from version 2.6 enforce this in
> this patch.
> 
> Signed-off-by: Bharata B Rao <address@hidden>

I've been kind of lost in the back and forth about
threads/cores/sockets.

What, in the end, is the rationale for allowing partially filled
sockets, but not partially filled cores?

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

signature.asc
Description: PGP signature