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Bug 653972

Summary: qcow2: Backport performance related patches
Product: Red Hat Enterprise Linux 6 Reporter: Kevin Wolf <kwolf>
Component: qemu-kvmAssignee: Kevin Wolf <kwolf>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: high Docs Contact:
Priority: low    
Version: 6.1CC: mjenner, mkenneth, tburke, virt-maint, wquan
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: qemu-kvm-0.12.1.2-2.122.el6 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-05-19 11:34:09 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: 580951    

Description Kevin Wolf 2010-11-16 14:55:16 UTC
RHEL 6.0 suffers from qcow2 being slow, especially during cluster allocations. Upstream has got a number of improvements since then, which need to be backported. They include patches to reduce the number of cache flushes (for cluster allocation) as well as avoiding bounce buffers in the usual read/write paths (should help with already allocated clusters, too).

Comment 7 Quan Wenli 2011-04-07 02:52:39 UTC
Benchmark iozone test with qemu-kvm-0.12.1.2-2.113.el6.x86_64(rhel6.0)and qemu-kvm-0.12.1.2-2.152.el6.x86_64 (rhel6.1)and the results was the average of 3
iterations. 
iozone ci:
incache:iozone -a -i 0 -i 1 -s ${incache}k -r 64k -w -+u -R ./test -f /mnt/t1
dio:iozone -a -i 0 -i 1 -s ${incache}k -r 64k -I -w -+u  -R ./test -f /mnt/t2
outcache:iozone -a -i 0 -i 1 -s ${outcache}k -r 64k -w -+u  -R ./test -f /mnt/t3


Qcow2-local qcow2 cache=none elevator=deadline 		
Type                    Rhel6.0-virtio  Rhel6.1-virtio	Improvement%
Dio-Write               2982.33         111403.67       3635.46%
Dio-Rewrite             126111.67       127007.33       0.71%
Dio-Read                152177.33       148669.67       -2.30%
Dio-Reread              153957          151804          -1.40%
Incache-Write           33806.33        176658.67       422.56%
Incache-ReWrite         153125          179184.67       17.02%
Incache-Read            224914.67       995947          342.81%
Incache-Reread          608146.67       980144.67       61.17%
Out-of-Cache-Write      28324.67        156221          451.54%
Out-of-Cache-ReWrite    131248.67       156416          19.18%
Out-of-Cache-Read       122599          149164          21.67%
Out-of-Cache-Reread     121197         148777.33        22.76%
			
Qcow2-nfs qcow2 cache=none elevator=dealine		
Type                    Rhel6.0-virtio  Rhel6.1-virtio	Improvement%	
Dio-Write               43287           55643.33        28.55%
Dio-Rewrite             62998.67        60435           -4.07%
Dio-Read                58227.67        57521.67        -1.21%
Dio-Reread              58375           57936.33        -0.75%
Incache-Write           105898          133944.67       26.48%
Incache-ReWrite         131408          93042           -29.20%
Incache-Read            194638.33       956375.67	391.36%
Incache-Reread          577811.67       810256.33       40.23%
Out-of-Cache-Write      90921.67        100638          10.69%
Out-of-Cache-ReWrite    93297.33        76711.67        -17.78%
Out-of-Cache-Read       53543           58324.33        8.93%
Out-of-Cache-Reread     64981.33        83918           29.14%

From results,we could see qcow2 has been gotten highly improvements from dio-wirte,incache-write ,incache-Read,Out-of-Cache-Write Out-of-Cache-Reread secnarios.
So it's pass.~~

Comment 8 Quan Wenli 2011-04-08 06:06:33 UTC
According comment #7 ,change the bus status to verified.thanks~~

Comment 10 errata-xmlrpc 2011-05-19 11:34:09 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-2011-0534.html

Comment 11 errata-xmlrpc 2011-05-19 13:00:13 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-2011-0534.html