On Thu, Feb 08, 2024 at 08:35:12AM -0800, Andrea Bolognani wrote: > 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? I'm trying to discourage it, though their latest reply actually indicates they want to report 'clusters' and 'modules' as distinct concepts, so we've got even more to do on libvirt side :-) https://lists.nongnu.org/archive/html/qemu-devel/2024-02/msg00052.html > > > 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, ...? Honestly don't know, its all a matter for what HW vendors choose todo. > 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. Sure. Mostly what this points out is that we don't have any reporting of available topology features in domain capabilities. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| _______________________________________________ Devel mailing list -- devel@xxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxx
