Public bug reported: -kvm flavor has CONFIG_NR_CPUS=64 although -generic has CONFIG_NR_CPUS=8192 these days.
It will be a problem especially when launching a VM on top of a hypervisor with more than 64 CPU threads available. Then the guest can only use up to 64 vCPUs even when more vCPUs are allocated by a hypervisor. I've checked the latest available package for Jammy, but there was no change around CONFIG_NR_CPUS. https://launchpad.net/ubuntu/+source/linux-kvm/5.15.0-1003.3 $ lsb_release -r Release: 20.04 $ dpkg -S /boot/config* linux-modules-5.4.0-105-generic: /boot/config-5.4.0-105-generic linux-modules-5.4.0-1059-kvm: /boot/config-5.4.0-1059-kvm $ grep CONFIG_NR_CPUS /boot/config* /boot/config-5.4.0-105-generic:CONFIG_NR_CPUS_RANGE_BEGIN=8192 /boot/config-5.4.0-105-generic:CONFIG_NR_CPUS_RANGE_END=8192 /boot/config-5.4.0-105-generic:CONFIG_NR_CPUS_DEFAULT=8192 /boot/config-5.4.0-105-generic:CONFIG_NR_CPUS=8192 /boot/config-5.4.0-1059-kvm:CONFIG_NR_CPUS_RANGE_BEGIN=2 /boot/config-5.4.0-1059-kvm:CONFIG_NR_CPUS_RANGE_END=512 /boot/config-5.4.0-1059-kvm:CONFIG_NR_CPUS_DEFAULT=64 /boot/config-5.4.0-1059-kvm:CONFIG_NR_CPUS=64 ** Affects: linux-kvm (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1967131 Title: CONFIG_NR_CPUS=64 in -kvm is too low compared to -generic To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-kvm/+bug/1967131/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
