Bug 1505576

Summary: Cannot specify proper CPU topology for 4-socket broadwell (24 cores per socket)
Product: [oVirt] ovirt-engine Reporter: djdumas
Component: BLL.VirtAssignee: Tomas Jelinek <tjelinek>
Status: CLOSED CURRENTRELEASE QA Contact: Liran Rotenberg <lrotenbe>
Severity: high Docs Contact:
Priority: unspecified    
Version: 4.1.7CC: bugs, ehabkost, knoel, michal.skrivanek, mtessun, rsibley, srao, tjelinek
Target Milestone: ovirt-4.1.8Flags: rule-engine: ovirt-4.1+
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
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.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2017-12-11 16:31:01 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: Virt RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1458754    
Bug Blocks:    

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.