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Bug 624769 - Blacklist vhost_net
Summary: Blacklist vhost_net
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.0
Hardware: All
OS: Linux
low
urgent
Target Milestone: rc
: ---
Assignee: Alex Williamson
QA Contact: Virtualization Bugs
URL:
Whiteboard:
: 624746 (view as bug list)
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2010-08-17 17:20 UTC by Alex Williamson
Modified: 2013-01-09 23:02 UTC (History)
12 users (show)

Fixed In Version: qemu-kvm-0.12.1.2-2.111.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2010-11-10 21:27:38 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
result for 109 (vhost) against 111 virtio-net (80.62 KB, application/octet-stream)
2010-08-19 13:45 UTC, Lawrence Lim 		no flags Details
virtio-net-Rhel6-vs-Rhel5.5 (59.85 KB, application/vnd.oasis.opendocument.spreadsheet)
2010-08-26 03:11 UTC, Quan Wenli 		no flags Details
result for rhel6 qemu 113 vs rhel6 qemu 111 vs rhel 5.5 GA in virtio-userspace . (66.44 KB, application/vnd.oasis.opendocument.spreadsheet)
2010-08-27 08:15 UTC, Quan Wenli 		no flags Details
View All

Description Alex Williamson 2010-08-17 17:20:57 UTC 
Description of problem:
vhost_net is showing stability issues, blacklist.

Version-Release number of selected component (if applicable):
qemu-kvm-0.12.1.2-2.110.el6.x86_64

How reproducible:
BZs: 623552, 623735, 623915

Steps to Reproduce:
1.
2.
3.
  
Actual results:


Expected results:


Additional info:
Comment 1 Alex Williamson 2010-08-17 17:32:42 UTC 
brew build, including bz624767 fix:

https://brewweb.devel.redhat.com/taskinfo?taskID=2686099
Comment 2 Bill Burns 2010-08-17 17:53:09 UTC 
*** Bug 624746 has been marked as a duplicate of this bug. ***
Comment 3 Andrew Cathrow 2010-08-17 18:06:03 UTC 
I see the patch is to blacklist vhost-net but is that the right fix?

vhost-net isn't loaded automatically it's explicitly loaded by /etc/sysconfig/modules/kvm.modules

So I think the fix should be to remove that line from kvm.modules  - see BZ596891
Comment 4 Alex Williamson 2010-08-17 18:13:51 UTC 
(In reply to comment #3)
> I see the patch is to blacklist vhost-net but is that the right fix?
> 
> vhost-net isn't loaded automatically it's explicitly loaded by
> /etc/sysconfig/modules/kvm.modules
> 
> So I think the fix should be to remove that line from kvm.modules  - see
> BZ596891

If we only remove the line in kvm.modules, what stops a user, or even gives them any indication, that they shouldn't use vhost_net?  Adding a /etc/modprobe.d/blacklist-kvm.conf stops both kvm.modules from loading it, and helps the user know they shouldn't try it.
Comment 5 Alex Williamson 2010-08-17 18:23:33 UTC 
brew with only the blacklist change:

https://brewweb.devel.redhat.com/taskinfo?taskID=2686282
Comment 10 Lawrence Lim 2010-08-19 13:45:11 UTC 
Created attachment 439688 [details]
result for 109 (vhost) against 111 virtio-net

Seems we have a performance drop with small packets after blacklisting.
Comment 11 Alex Williamson 2010-08-19 14:00:17 UTC 
(In reply to comment #10)
> 
> Seems we have a performance drop with small packets after blacklisting.

This is expected.
Comment 13 Quan Wenli 2010-08-26 03:11:31 UTC 
Created attachment 441098 [details]
virtio-net-Rhel6-vs-Rhel5.5

result for rhel 6 vs rhel 5.5 GA in virtio-userspace .
Comment 14 Alex Williamson 2010-08-26 04:08:32 UTC 
Quan, would it be possible to do one more comparison using this brew build?

https://brewweb.devel.redhat.com/taskinfo?taskID=2709720
Comment 15 Quan Wenli 2010-08-27 08:15:13 UTC 
Created attachment 441431 [details]
result for rhel6 qemu 113 vs rhel6 qemu 111  vs rhel 5.5 GA in virtio-userspace .
Comment 16 Quan Wenli 2010-08-31 02:59:22 UTC 
confirmed this bug with Alex Williamson , We mark this verified.

Thanks~~
Comment 17 releng-rhel@redhat.com 2010-11-10 21:27:38 UTC 
Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.
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