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 653972 - qcow2: Backport performance related patches
Summary: qcow2: Backport performance related patches
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.1
Hardware: Unspecified
OS: Unspecified
low
high
Target Milestone: rc
: ---
Assignee: Kevin Wolf
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks: Rhel6KvmTier1
TreeView+ depends on / blocked
 
Reported: 2010-11-16 14:55 UTC by Kevin Wolf
Modified: 2013-01-09 23:20 UTC (History)
5 users (show)

Fixed In Version: qemu-kvm-0.12.1.2-2.122.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-05-19 11:34:09 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:0534 0 normal SHIPPED_LIVE Important: qemu-kvm security, bug fix, and enhancement update 2011-05-19 11:20:36 UTC

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
Note You need to log in before you can comment on or make changes to this bug.