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 1022548 - Read/Randread/Randrw performance regression
Summary: Read/Randread/Randrw performance regression
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.5
Hardware: x86_64
OS: Linux
urgent
urgent
Target Milestone: rc
: ---
Assignee: Fam Zheng
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks: 1025138 1025596
TreeView+ depends on / blocked
 
Reported: 2013-10-23 13:49 UTC by Xiaomei Gao
Modified: 2014-10-14 06:53 UTC (History)
14 users (show)

Fixed In Version: qemu-kvm-0.12.1.2-2.417.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
: 1025138 (view as bug list)
Environment:
Last Closed: 2014-10-14 06:53:31 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2014:1490 0 normal SHIPPED_LIVE qemu-kvm bug fix and enhancement update 2014-10-14 01:28:27 UTC

Comment 4 Kevin Wolf 2013-10-25 07:08:23 UTC 
Can you track the regression down to a specific build or smaller set of builds?
Comment 5 Quan Wenli 2013-10-25 08:33:14 UTC 
(In reply to Kevin Wolf from comment #4)
> Can you track the regression down to a specific build or smaller set of
> builds?

Kevin, commment #0 has mentioned that this regression was introduced by following patch from qemu-kvm-0.12.1.2-2.391.el6.
 - kvm-block-Produce-zeros-when-protocols-reading-beyond-en.patch [bz#848070]
Comment 6 Xiaomei Gao 2013-10-25 12:34:41 UTC 
Btw, kvm_exits frequency is much higher compared to old version on virtio_scsi driver in read/randread/randrw category. Besides, we can also see the issue on local format image with virtio_scsi driver in randrw category, but IOPS does not degrades on local raw format image. Through bisect analysis, we found the high kvm_exits frequency on virtio_scsi driver is also introduced by the patch in comment #5
Comment 8 Xiaomei Gao 2013-10-29 08:44:44 UTC 
We could see a little performance degradation in randrw category on local format image. Besides, kvm_exits frequency is much higher on virtio_scsi driver in randrw category. Through bisect analysis, they are both introduced by the patch in comment #5, so i changed the title.
Comment 15 Ademar Reis 2013-11-09 00:47:22 UTC 
QE found issues with the fix while testing Bug 1025596 (z-stream clone of this one) and we need additional patches. Moving it back to assigned, Fam is taking care of it.
Comment 16 Qunfang Zhang 2013-11-13 03:20:24 UTC 
Hi, Fam

As we already have bug 1025596 to track the z-stream build, so if I understand correctly, this one is for 6.6 and we should have a rhel6.6 build (like -416) in the "Fixed In Version". :) correct me if I'm wrong. 

Thanks a lot for your tracking up on this issue so that QE could have a fixed build earlier to test!

Qunfang
Comment 17 Fam Zheng 2013-11-13 03:41:01 UTC 
(In reply to Qunfang Zhang from comment #16)
> Hi, Fam
> 
> As we already have bug 1025596 to track the z-stream build, so if I
> understand correctly, this one is for 6.6 and we should have a rhel6.6 build
> (like -416) in the "Fixed In Version". :) correct me if I'm wrong. 
> 
> Thanks a lot for your tracking up on this issue so that QE could have a
> fixed build earlier to test!
> 

Yes you are right. The status was a mistake.

Moving back to POST.

Fam
Comment 21 errata-xmlrpc 2014-10-14 06:53:31 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2014-1490.html
Note You need to log in before you can comment on or make changes to this bug.