[24.04 FEAT] [VS2029] KVM: Provide virtual CPU topology to guests - qemu part

[bugproxy]

Currently, KVM guests will see an evenly distributed CPU topology, where every CPU resides on a separate drawer. This may not be optimal for scheduling decisions. The goal of this feature is to allow to specify a virtual CPU topology which can help to configure the guest for better performance. The full range of topology nodes should be configurable (drawer -> book -> chip -> core -> thread).

This feature has a kernel, qemu and libvirt part.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2022-08-01 09:54 EDT-------
The qemu part of this feature will not make it in time for kinetic FF, therefore we have to move it to Ubuntu 23.04.

Changing target milestone to: 23.04

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2023-02-06 13:40 EDT-------
Thanks Pierre for the update:
The QEMU part of this feature will not be ready in time for lunar FF as the patches are still in discussion in the QEMU mailing list.

Therefore, we need to postpone this feature to Ubuntu 23.10.

Changing target milestone to ==> 23.10

Please note that this feature has also a kernel part which went upstream with kernel 6.0 (see other Bug 199137 - LP1983224 : [23.04 FEAT] [VS2029] KVM: Provide virtual CPU topology to guests - kernel part)

[Frank Heimes (fheimes)]

Thx for the update, I'll adjust the ticket accordingly.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2023-08-16 11:36 EDT-------
The QEMU part of this feature is not yet available, hence missing Mantic FF.

Therefore, we need to postpone this feature to Ubuntu 24.04.

==> Changing target milestone to "24.04"

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2024-01-21 15:06 EDT-------
Thanks Nina for confirming that this feature is included in qemu 8.2 and for providing the Commits:

219922ef9b ("tests/avocado: s390x cpu topology bad move")
22ac7809bb ("tests/avocado: s390x cpu topology dedicated errors")
944e03006d ("tests/avocado: s390x cpu topology test socket full")
471676bfd2 ("tests/avocado: s390x cpu topology test dedicated CPU")
16ab722edb ("tests/avocado: s390x cpu topology entitlement tests")
cb042c73f3 ("tests/avocado: s390x cpu topology polarization")
e5bc49d54d ("tests/avocado: s390x cpu topology core")
0d177cdd2b ("docs/s390x/cpu topology: document s390x cpu topology")
154893a784 ("qapi/s390x/cpu topology: add query-s390x-cpu-polarization command")
1cfe52b782 ("qapi/s390x/cpu topology: CPU_POLARIZATION_CHANGE QAPI event")
bb2df37a62 ("machine: adding s390 topology to info hotpluggable-cpus")
ad2d1afc1d ("machine: adding s390 topology to query-cpu-fast")
a457c2ab5a ("qapi/s390x/cpu topology: set-cpu-topology qmp command")
f530b9e7da ("target/s390x/cpu topology: activate CPU topology")
af37bad52e ("s390x/cpu topology: interception of PTF instruction")
3d6e75f4df ("s390x/cpu topology: resetting the Topology-Change-Report")
a67f05b391 ("s390x/sclp: reporting the maximum nested topology entries")
f4f54b582f ("target/s390x/cpu topology: handle STSI(15) and build the SYSIB")
c809bbc8e9 ("s390x/cpu topology: add topology entries on CPU hotplug")
5de1aff255 ("CPU topology: extend with s390 specifics")
3da4aef81c ("qapi: machine.json: change docs regarding CPU topology")

[Frank Heimes (fheimes)]

Thx a lot - that's great and good to know!