Bug 473114 - RHEL 5.3: allow virtio_net support larger MTU sizes
RHEL 5.3: allow virtio_net support larger MTU sizes
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
high Severity high
: rc
: ---
Assigned To: Mark McLoughlin
Martin Jenner
Depends On:
  Show dependency treegraph
Reported: 2008-11-26 10:55 EST by Mark McLoughlin
Modified: 2009-01-20 14:58 EST (History)
6 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2009-01-20 14:58:56 EST
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
virtio_net-jumbo-frame-support.patch (1.64 KB, patch)
2008-11-26 12:46 EST, Mark McLoughlin
no flags Details | Diff

  None (edit)
Description Mark McLoughlin 2008-11-26 10:55:00 EST
Currently, the virtio_net driver doesn't support setting it's MTU size to more
than 1500 bytes:

  $> ip link set eth0 mtu 9000
  SIOCSIFMTU: Invalid argument

In order to gain the performance improvement resulting from less packet
overhead, it's quite common for customers to configure their network so that
the entire path between two nodes support jumbo frames (i.e. frame size of 9000

Since virtio_net doesn't support this, it's impossible to obtain this benefit with
KVM/virtio guests.

The patch to implement this support is quite trivial and has been just submitted upstream here:

Comment 2 Mark McLoughlin 2008-11-26 12:46:23 EST
Created attachment 324771 [details]
Comment 5 Don Zickus 2008-12-09 16:05:39 EST
in kernel-2.6.18-126.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5
Comment 8 errata-xmlrpc 2009-01-20 14:58:56 EST
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.


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