Bug 665360

Summary: vhost-net/kvm lacks fixes/optimizations in net-next as of Dec 23
Product: Red Hat Enterprise Linux 6 Reporter: Michael S. Tsirkin <mst>
Component: kernelAssignee: Michael S. Tsirkin <mst>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: low    
Version: 6.1CC: jasowang, lihuang, tburke, wquan
Target Milestone: rc   
Target Release: 6.1   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: kernel-2.6.32-112.el6 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-05-23 20:32:44 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 580954    
Attachments:
Description Flags
vhost-net rhel6.0 vs rhel6.1
none
vhost-net rhel6.0 vs rhel6.1 megabyte/cpu none

Description Michael S. Tsirkin 2010-12-23 12:24:39 UTC 
Description of problem:
vhost-net and kvm modules in upstream have several optimizations
that give about 15-20% gain on small packet bandwidth,
and fix minor bugs.
The list of patches as of today:

kvm: fast-path msi injection with irqfd
vhost: get/put_user -> __get/__put_user
vhost: copy_to_user -> __copy_to_user
vhost: fix log ctx signalling
vhost: fix return code for log_access_ok()
vhost-net: batch use/unuse mm
drivers/vhost/vhost.c: delete double assignment
vhost: put mm after thread stop
vhost: stop worker only if created
vhost: replace vhost_workqueue with per-vhost kthread

Version-Release number of selected component (if applicable):
kernel-2.6.32-92.el6
Comment 1 RHEL Program Management 2010-12-23 12:50:22 UTC 
This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.
Comment 2 RHEL Program Management 2010-12-23 13:10:27 UTC 
This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.
Comment 4 Aristeu Rozanski 2011-02-03 15:28:51 UTC 
Patch(es) available on kernel-2.6.32-112.el6
Comment 7 Quan Wenli 2011-04-08 05:16:26 UTC 
Created attachment 490700 [details]
vhost-net rhel6.0 vs rhel6.1

Attach the test result of vhost-net rhel6.1/rhel6.0.
See high improvment with small packet under guest <->exhost ,and guest <-> exguest scenarios compared with rhel6.1 vhost-net ,but see obvious performance degradation with UDP (R) and TCP (S) under guest <-> host scenario compared with rhel6.1 vhost-net.
Comment 9 Quan Wenli 2011-04-19 07:53:04 UTC 
Created attachment 493117 [details]
vhost-net rhel6.0 vs rhel6.1 megabyte/cpu

attach  megabyte/cpu sheet base on comment #7's sheet. only focus on samll packets (< MTU) ,rhel6.1 vhost get high improvment in most of the scenarios/protocols expect for TCP (S) from host to guest compared with rhel6.0 vhost.
Comment 10 Quan Wenli 2011-04-21 08:42:40 UTC 
(In reply to comment #9)
> Created attachment 493117 [details]
> vhost-net rhel6.0 vs rhel6.1 megabyte/cpu
> 
> attach  megabyte/cpu sheet base on comment #7's sheet. only focus on samll
> packets (< MTU) ,rhel6.1 vhost get high improvment in most of the
> scenarios/protocols expect for TCP (S) from host to guest compared with rhel6.0
> vhost.

hi mst 

what's your comments? as comment #9 ,could i verify it as pass or something else?
Comment 11 Michael S. Tsirkin 2011-04-26 10:12:06 UTC 
to comment 10: yes, I think it's ok.
Comment 12 Quan Wenli 2011-04-26 10:37:11 UTC 
base on comment #9 #11, change the bug status to verified.
Comment 13 errata-xmlrpc 2011-05-23 20:32:44 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0542.html