RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1071888 - Libvirt should calculate and pass vectors parameter correclty (should be 2N+2) to qemu command line for multiqueue virtio net device
Summary: Libvirt should calculate and pass vectors parameter correclty (should be 2N+2...
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt
Version: 7.0
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Michal Privoznik
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On: 1066209
Blocks:
TreeView+ depends on / blocked
 
Reported: 2014-03-03 12:10 UTC by jason wang
Modified: 2014-06-18 01:03 UTC (History)
21 users (show)

Fixed In Version: libvirt-1.1.1-26.el7
Doc Type: Bug Fix
Doc Text:
Clone Of: 1066209
Environment:
Last Closed: 2014-06-13 12:21:14 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Comment 1 Michal Privoznik 2014-03-03 12:38:34 UTC 
Jason,

can you please update the linux-kvm.org wiki so I have something to point to?

The http://www.linux-kvm.org/page/Multiqueue#Enable_MQ_feature page still lists the old default.
Comment 4 jason wang 2014-03-04 02:44:25 UTC 
(In reply to Michal Privoznik from comment #1)
> Jason,
> 
> can you please update the linux-kvm.org wiki so I have something to point to?
> 
> The http://www.linux-kvm.org/page/Multiqueue#Enable_MQ_feature page still
> lists the old default.

Thanks for the reminding.

Have changed the wiki to use 2N+2.
Comment 5 Michal Privoznik 2014-03-04 09:48:28 UTC 
Patch proposed upstream:

https://www.redhat.com/archives/libvir-list/2014-March/author.html
Comment 6 Michal Privoznik 2014-03-04 10:12:03 UTC 
To POST:

http://post-office.corp.redhat.com/archives/rhvirt-patches/2014-March/msg00076.html
Comment 8 Hu Jianwei 2014-03-07 03:31:21 UTC 
Verified as below:

Version:
libvirt-1.1.1-26.el7.x86_64
qemu-kvm-rhev-1.5.3-52.el7.x86_64
kernel-3.10.0-105.el7.x86_64

1. Set queues=6, libvirt can pass 2*6+2 to vectors in qemu command line.
[root@intel-e5530-8-2 ~]# virsh dumpxml test| grep interface -A8
    <interface type='network'>
      <mac address='52:54:00:85:26:85'/>
      <source network='default'/>
      <target dev='vnet1'/>
      <model type='virtio'/>
      <driver name='vhost' queues='6'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
...
[root@intel-e5530-8-2 ~]# ps aux | grep test |grep -v grep| sed 's/-device/\n-device/g' | grep "virtio-net-pci"
-device virtio-net-pci,mq=on,vectors=14,netdev=hostnet0,id=net0,mac=52:54:00:85:26:85,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 

2. Set queues=1 or omitted this element, libvirt would not pass value to vectors in qemu command line, this is expected results from code patch.
[root@intel-e5530-8-2 ~]# virsh dumpxml test| grep interface -A8
    <interface type='network'>
      <mac address='52:54:00:85:26:85'/>
      <source network='default'/>
      <target dev='vnet1'/>
      <model type='virtio'/>
      <driver name='vhost'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
...
[root@intel-e5530-8-2 ~]# ps aux | grep test |grep -v grep| sed 's/-device/\n-device/g' | grep "virtio-net-pci"
-device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:85:26:85,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 


We can get the expected result, changed to verified.
Comment 9 Ludek Smid 2014-06-13 12:21:14 UTC 
This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.
Note You need to log in before you can comment on or make changes to this bug.