Bug 1505576 - Cannot specify proper CPU topology for 4-socket broadwell (24 cores per socket)
Summary: Cannot specify proper CPU topology for 4-socket broadwell (24 cores per socket)
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: ovirt-engine
Classification: oVirt
Component: BLL.Virt
Version: 4.1.7
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: ovirt-4.1.8
: ---
Assignee: Tomas Jelinek
QA Contact: Liran Rotenberg
URL:
Whiteboard:
Depends On: 1458754
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-10-23 21:50 UTC by djdumas
Modified: 2017-12-11 16:31 UTC (History)
8 users (show)

Fixed In Version:
Doc Type: Enhancement
Doc Text:
Feature: Support more than 16 cores per socket Reason: Modern CPUs do support more, qemu does not have problem with that, this restriction just artificially constrained the user to create a virtual HW which matches the physical Result: 254 cores per socket is now supported.
Clone Of:
Environment:
Last Closed: 2017-12-11 16:31:01 UTC
oVirt Team: Virt
Embargoed:
rule-engine: ovirt-4.1+

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
oVirt gerrit 83277 0 master MERGED core: increase num of cores per socket 2020-03-27 05:15:46 UTC
oVirt gerrit 84409 0 ovirt-engine-4.1 MERGED core: increase num of cores per socket 2020-03-27 05:15:46 UTC

Description djdumas 2017-10-23 21:50:00 UTC 
Description of problem:
SAP HANA is NUMA-aware and uses host topology for proper process placement.  Passing proper NUMA topology to the guest is critical for performance.
Cannot pass proper topology for Broadwell (4 socket, 24 cores/socket, 2 threads)
Untested but probably can't pass Skylake topology either - (up to 28 cores per socket)


Version-Release number of selected component (if applicable):
At least 4.1.5 through 4.1.7


How reproducible: always


Steps to Reproduce:
1. Try to create a guest via RHV manager interface with 4 sockets, 24 cores per socket, 2 threads
2.
3.

Actual results: Operation Failed: [Cannot add VM. Maximum number of cpu per socket exceeded]


Expected results: succeeds with proper topology


Additional info:
Related: BZ 1458754
Comment 5 Liran Rotenberg 2017-12-05 08:03:35 UTC 
Verified on 4.1.8.2-0.1.el7.

Step of verification:
1. Created a VM with 4 sockets, 24 cores per socket, 2 threads.

Result:
VM added successfully.
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