| Summary: | AMD Magny-cours processors have wrong topology | ||
|---|---|---|---|
| Product: | [Community] Virtualization Tools | Reporter: | Tad Kollar <tad.kollar> |
| Component: | libvirt | Assignee: | Libvirt Maintainers <libvirt-maint> |
| Status: | CLOSED DEFERRED | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | unspecified | CC: | crobinso, mzhan, rbalakri, xen-maint |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2016-03-23 21:02:35 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
Sorry this never received a response. I'm not sure if this was ever fixed since I don't have that system. If you can still reproduce with newer libvirt please reopen this bug and provide /proc/cpuinfo |
Description of problem: Magny-cours processors with 12 cores per physical socket should be detected as either having one socket and 12 cores, or possibly two sockets with 6 cores each. Instead they are detected as one socket and six cores, so only half the cores are usable by libvirt. Version-Release number of selected component (if applicable): 0.9.11, 0.9.10, and possibly more after 0.9.4. How reproducible: Always. Steps to Reproduce: 1. Run virsh capabilities on a host with an AMD Opteron 6174 or similar processor 2. Examine the topology entry 3. Actual results: <capabilities> <host> <uuid>48385147-3600-0030-48fe-003048fe7e7e</uuid> <cpu> <arch>x86_64</arch> <model>Opteron_G3</model> <vendor>AMD</vendor> <topology sockets='4' cores='6' threads='1'/> ... Expected results: <capabilities> <host> <uuid>48385147-3600-0030-48fe-003048fe7e7e</uuid> <cpu> <arch>x86_64</arch> <model>Opteron_G3</model> <vendor>AMD</vendor> <topology sockets='4' cores='12' threads='1'/> ... Additional info: There seems to be confusion between the topology reported by numa and the physical topology that's causing the problem. Numa detects 8 sockets with 6 cores each, yet there are four physical sockets with 12 cores. The issue did not exist in libvirt 0.9.4.