Bug 881674 - 20% performance degradation on random write when 8k blocksize with 16 threads over NFS backend
Summary: 20% performance degradation on random write when 8k blocksize with 16 thread...
Keywords:
Status: CLOSED DUPLICATE of bug 916020
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.4
Hardware: Unspecified
OS: Unspecified
urgent
unspecified
Target Milestone: rc
: ---
Assignee: Kevin Wolf
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-11-29 10:21 UTC by Xiaomei Gao
Modified: 2013-04-22 10:46 UTC (History)
12 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2013-04-22 10:46:00 UTC
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)
random_write_8k_16.ffsb (958 bytes, application/octet-stream)
2012-11-30 04:09 UTC, Xiaomei Gao
no flags Details

Comment 4 Xiaomei Gao 2012-11-30 04:09:20 UTC
Created attachment 654781 [details]
random_write_8k_16.ffsb

Comment 5 Amit Shah 2012-11-30 07:48:12 UTC
(From discusison on irc), please delete the qcow2 image file before each run, to eliminate any caching effects.  However, I doubt such effects are being seen in these results.

Comment 6 Xiaomei Gao 2012-11-30 09:17:50 UTC
(In reply to comment #5)
> (From discusison on irc), please delete the qcow2 image file before each
> run, to eliminate any caching effects.  However, I doubt such effects are
> being seen in these results.

Okay. Once the test result is done, i will put results here.

Thanks
xiaomei

Comment 10 Quan Wenli 2012-12-07 03:37:53 UTC
Amit Shah

There are about 40 qemu-kvm versions between qemu-kvm-295 (good result) and qemu-kvm-335 (bad result), and almost all of them have been removed from brew,any suggestion about bisect them ?

Comment 11 Xiaomei Gao 2012-12-07 11:27:52 UTC
hi, all

Try test the issue for 3 times on qemu-kvm-316 and get the results:
408 MB/s 422 MB/s 450MB/s

On qemu-kvm-329 and get the results:
257MB/s 339 MB/s 282MB/s

So we can narrow the version test, that is 316~329 qemu-kvm version, but it is removed from our brew now.

Comment 16 RHEL Program Management 2012-12-14 07:55:01 UTC
This request was not resolved in time for the current release.
Red Hat invites you to ask your support representative to
propose this request, if still desired, for consideration in
the next release of Red Hat Enterprise Linux.

Comment 32 Kevin Wolf 2013-04-22 10:46:00 UTC
Thanks for all the testing. So the fix is already in, closing.

*** This bug has been marked as a duplicate of bug 916020 ***


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