Bug 865305 - fuse: backport scatter-gather direct IO [rhel-6.3.z]
fuse: backport scatter-gather direct IO [rhel-6.3.z]
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel (Show other bugs)
Unspecified Unspecified
urgent Severity high
: rc
: ---
Assigned To: Frantisek Hrbata
Red Hat Kernel QE team
: ZStream
Depends On: 858850
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Reported: 2012-10-11 04:00 EDT by RHEL Product and Program Management
Modified: 2013-02-07 08:20 EST (History)
15 users (show)

See Also:
Fixed In Version: kernel-2.6.32-279.22.1.el6
Doc Type: Bug Fix
Doc Text:
Filesystem in Userspace (FUSE) did not implement scatter-gather direct I/O optimally. Consequently, the kernel had to process an extensive number of FUSE requests, which had a negative impact on system performance. This update applies a set of patches which improves internal request management for other features, such as readahead. FUSE direct I/O overhead has been significantly reduced to minimize negative effects on system performance.
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Clone Of:
Last Closed: 2013-02-05 14:56:12 EST
Type: ---
Regression: ---
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Documentation: ---
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2013:0223 normal SHIPPED_LIVE Moderate: kernel security and bug fix update 2013-02-05 19:52:09 EST

  None (edit)
Description RHEL Product and Program Management 2012-10-11 04:00:26 EDT
This bug has been copied from bug #858850 and has been proposed
to be backported to 6.3 z-stream (EUS).
Comment 8 Ben England 2013-01-21 10:06:21 EST

see comment in https://bugzilla.redhat.com/show_bug.cgi?id=858850#c18 which describes how to get the test program and data.  I didn't realize you had a separate bz for this.  I think I can test the kernel for you now that I know where to find it.  You can too if you have 10-GbE and some storage with throughput similar to 10-GbE.  We really want this patch because it makes a huge difference, see the article at 


Best Regards, -ben
Comment 10 Ben England 2013-01-22 22:51:27 EST
so which rhel6.4 kernel should I test with?  We'll try the RHEL6.3 kernel ASAP.  I pulled RPMs in #c9 from Brew.
Comment 11 Monson Shao 2013-01-23 00:32:58 EST
(In reply to comment #10)
> so which rhel6.4 kernel should I test with?  We'll try the RHEL6.3 kernel
> ASAP.  I pulled RPMs in #c9 from Brew.

The rhel6.4 kernel has been tested in Bug 858850 .
So what you only need to do is pasting rhel6.3 kernel test result here, and I will do the rest. Thanks.
Comment 12 Ben England 2013-01-23 23:39:59 EST
I retested with above kernel 2.6.32-279.22.1.el6.x86_64 and 2.6.32-279.el6.x86_64 (RHEL6.3) and again I see a huge increase in throughput particularly with iozone reads from 1 or more guests inside the KVM host.  Data and graphs are at:


Let me know when this patch can be obtained via RHN updates to RHEL6.3.
Comment 15 errata-xmlrpc 2013-02-05 14:56:12 EST
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.


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