Re: Re: Re: Re: Re: [PATCH] docs: Improve documentation for dies and clusters
On Thu, Feb 08, 2024 at 04:22:11PM +0000, Daniel P. Berrangé wrote:
On Thu, Feb 08, 2024 at 08:13:26AM -0800, Andrea Bolognani wrote:
> AFAICT there's no x86_64 (or ppc64, or s390x, or ...) machine type
> that can use CPU clusters.
I believe x86 should be gaining CPU cluster support in QEMU, though
the current patch is suggesting to call them 'modules' when configuring
the guest, just to absolutely maximise confusion when linux calls
them 'clusters'.
Lovely. Any chance we're still in time to prevent that specific
trainwreck from happening?
> So if you're planning to run a same-architecture VM (most
common use
> case) you are not going to be able to use CPU clusters, which might
> be confusing considering that CPU clusters appear to be supported by
> your host CPU according to the capabilities XML.
On x86 AMD CPUs will report multiple dies while new Intel CPUs will
report multiple clusters. In both cases, you'll be able to run a
guest with multiple dies, if desire, and in future, with multiple
clusters.
Are you aware of similar plans on the Arm side, to allow the use of
multiple dies for guests? What about ppc64, s390x, riscv64, ...?
Let's try one more time:
Note that, even if this attribute is present, you might not be able
to define guests with multiple CPU dies.
This should accurately describe both today's situation, as well as
whatever might come in the future to whatever architecture.
--
Andrea Bolognani / Red Hat / Virtualization