Bug 1479448

Summary: vm boot very slowly running with vhost-user when cpuset is configured
Product: Red Hat Enterprise Linux 7 Reporter: Wei Huang (AMD) <wehuang>
Component: qemu-kvm-rhevAssignee: Wei Huang <wei>
Status: CLOSED WORKSFORME QA Contact: Virtualization Bugs <virt-bugs>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 7.4-AltCC: chayang, drjones, hhuang, jcm, juzhang, knoel, michen, rbalakri, virt-maint, wtownsen
Target Milestone: rcKeywords: OtherQA
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Hardware: aarch64   
OS: Unspecified   
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Last Closed: 2017-09-25 13:23:31 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Blocks: 1174832    

Description Wei Huang (AMD) 2017-08-08 14:52:32 UTC 
=== Description ===
We saw VM booting very slowly with the following two settings in the guest config file:
  1. cpuset
  2. vhost-user

It seems this problem happened on 4.11.0-17.el7a.aarch64 kernel, but not with kernel 4.11.0-10.el7a.aarch64. We also found that, at least on arm1 (a Gigabyte machine owned by network team) machine, lower index of physical cores (e.g. 6, 7, 8, 9) will cause the problem. But a larger index numbers allow VM to boot successfully.

==== Setting Details ====
1. cpuset
  <vcpu placement='static' cpuset='6-9'>4</vcpu>
  <cputune>
    <vcpupin vcpu='0' cpuset='6'/>
    <vcpupin vcpu='1' cpuset='7'/>
    <vcpupin vcpu='2' cpuset='8'/>
    <vcpupin vcpu='3' cpuset='9'/>
  </cputune>
2. vhost user
    <interface type='vhostuser'>
      <mac address='00:be:ef:00:ba:be'/>
      <source type='unix' path='/usr/local/var/run/openvswitch/vhost1' mode='client'/>
      <model type='virtio'/>
      <driver queues='4'>
        <host mrg_rxbuf='off'/>
      </driver>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
    </interface>
Comment 2 Wei Huang (AMD) 2017-09-23 03:34:29 UTC 
We haven't seen this problem after a clean installation on failed machines. I am cc'ing the original reporter. If he can confirm that it has be resolved, we can close this BZ.
Comment 3 Bill Townsend 2017-09-25 13:23:31 UTC 
Yes, this has cleared up and I have not seen it again.