[ovs-discuss] userspace mode of ovs, UDP traffic max throughput is 150 Mb/s

Ethan Jackson ethan at nicira.com
Fri Jun 8 00:29:05 UTC 2012


> So upgrade to 1.7.0 (see from another post discussing on performance, but it
> is related to kernel mode) should not help, right?

Correct, performance improvements were targeted at kernel datapaths.
Some of those improvements may have impacted the userspace datapaths a
but, but I doubt they had a significant impact.

> Also, I am curious that how the QoS work in ovs? Does QoS use traffic
> control (tc)? If so, tc requires kernel support, which is not doable in
> userspace mode of ovs. correct me if I am wrong here.

Correct, it won't work.

> Just wondering if improving the performance of user space datapath is on
> schedule or just something with low priority?

As Ben said, very low priority for us.  Patches welcome.

Ethan

>
>
> On Thu, Jun 7, 2012 at 6:38 PM, Ethan Jackson <ethan at nicira.com> wrote:
>>
>> > Thanks, Jesse. Could you explain more details on what features are not
>> > available in the user space datapath?
>>
>> The main feature being performance.  That being the issue you're
>> running into, I would suggest switching.  Certain kinds of port types
>> aren't supported as well.  Tunneling and what not.
>>
>> Ethan
>>
>> >
>> >
>> > On Thu, Jun 7, 2012 at 6:05 AM, Jesse Gross <jesse at nicira.com> wrote:
>> >>
>> >> On Thu, Jun 7, 2012 at 12:52 PM, Dong Jin <jinanddong at gmail.com> wrote:
>> >> > I am running userspace mode of ovs with the following topology
>> >> >
>> >> > VM1(eth0) ---- (eth0)VM2(eth1) --- (eth0)VM3
>> >> >
>> >> > VM1 and VM3 are end hosts, and VM2 runs the userspace ovs daemon to
>> >> > emulate a two-port Ethernet switch.
>> >> >
>> >> > I sent UDP traffic from VM1 to VM3. Everything is received with 100
>> >> > Mb/s rate. However, for 200 Mb/s data rate, packet losses are
>> >> > observed
>> >> > (below is the log), and throughput is around 150 Mb/s. If I connect
>> >> > VM1 and VM3 directly without using VM2, it is fine to receive 200
>> >> > Mb/s
>> >> > or even high rate with no loss. It looks that ovs causes the packet
>> >> > drop and limit the throughput. Just wondering the reason and how to
>> >> > overcome this to emulate high data rate? Advices are very
>> >> > appreciated.
>> >>
>> >> The userspace datapath is primarily intended for testing and maximum
>> >> compatibility.  It does not have all of the features or performance of
>> >> the kernel module.
>> >
>> >
>> >
>> > _______________________________________________
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>> > discuss at openvswitch.org
>> > http://openvswitch.org/mailman/listinfo/discuss
>> >
>
>



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