SMT not supported by QEMU on AMD Ryzen CPU
Bug #1703506 reported by
A S
This bug affects 8 people
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
QEMU |
Expired
|
Undecided
|
Unassigned |
Bug Description
HyperThreading/SMT is supported by AMD Ryzen CPUs but results in this message when setting the topology to threads=2:
qemu-system-x86_64: AMD CPU doesn't support hyperthreading. Please configure -smp options properly.
Checking in a Windows 10 guest reveals that SMT is not enabled, and from what I understand, QEMU converts the topology from threads to cores internally on AMD CPUs. This appears to cause performance problems in the guest perhaps because programs are assuming that these threads are actual cores.
Software: Linux 4.12, qemu 2.9.0 host with KVM enabled, Windows 10 pro guest
Changed in qemu: | |
assignee: | nobody → Eduardo Habkost (ehabkost) |
Changed in qemu: | |
assignee: | Eduardo Habkost (ehabkost) → nobody |
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I can confirm this problem as it affects me, too on Ubuntu XENIAL, Kernel 4.10.0-26-generic