[ovs-discuss] Test Suit for traffic-control (QoS Rate-Limiting) in OVS
Ben Pfaff
blp at nicira.com
Wed Aug 14 17:07:27 UTC 2013
On Wed, Aug 14, 2013 at 12:22:26PM +0530, ashish yadav wrote:
> I am looking for test suite( test cases) for traffic-control (QoS
> Rate-Limiting) in OVS .
> It may include test cases with VLAN , bond etc interface also.
OVS does not include traffic control tests, because it delegates QoS to
the underlying kernel.
Q: I configured QoS, correctly, but my measurements show that it isn't
working as well as I expect.
A: With the Linux kernel, the Open vSwitch implementation of QoS has
two aspects:
- Open vSwitch configures a subset of Linux kernel QoS
features, according to what is in OVSDB. It is possible that
this code has bugs. If you believe that this is so, then you
can configure the Linux traffic control (QoS) stack directly
with the "tc" program. If you get better results that way,
you can send a detailed bug report to bugs at openvswitch.org.
It is certain that Open vSwitch cannot configure every Linux
kernel QoS feature. If you need some feature that OVS cannot
configure, then you can also use "tc" directly (or add that
feature to OVS).
- The Open vSwitch implementation of OpenFlow allows flows to
be directed to particular queues. This is pretty simple and
unlikely to have serious bugs at this point.
However, most problems with QoS on Linux are not bugs in Open
vSwitch at all. They tend to be either configuration errors
(please see the earlier questions in this section) or issues with
the traffic control (QoS) stack in Linux. The Open vSwitch
developers are not experts on Linux traffic control. We suggest
that, if you believe you are encountering a problem with Linux
traffic control, that you consult the tc manpages (e.g. tc(8),
tc-htb(8), tc-hfsc(8)), web resources (e.g. http://lartc.org/), or
mailing lists (e.g. http://vger.kernel.org/vger-lists.html#netdev).
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