Re: [RFC PATCH v2 6/6] hw/arm/virt: Replace smp_parse with one that prefers cores

[Andrew Jones]

On Tue, Apr 13, 2021 at 04:07:45PM +0800, Yanan Wang wrote:
> From: Andrew Jones <drjones@redhat.com>
> 
> The virt machine type has never used the CPU topology parameters, other
> than number of online CPUs and max CPUs. When choosing how to allocate
> those CPUs the default has been to assume cores. In preparation for
> using the other CPU topology parameters let's use an smp_parse that
> prefers cores over sockets. We can also enforce the topology matches
> max_cpus check because we have no legacy to preserve.
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> ---
>  hw/arm/virt.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)

Thanks, this patch matches [1]. Of course, I've always considered this
patch to be something of an RFC, though. Is there any harm in defaulting
to sockets over cores? If not, I wonder if we shouldn't just leave the
default as it is to avoid a mach-virt specific smp parser. The "no
topology" compat variable will keep existing machine types from switching
from cores to sockets, so we don't need to worry about that.

[1] 
https://github.com/rhdrjones/qemu/commit/c0670b1bccb4d08c7cf7c6957cc8878a2af131dd

Thanks,
drew