[ovs-discuss] On TCP_CRR test setup in "Accelerating Open vSwitch to “Ludicrous Speed”"

[Yousong Zhou]

Hi

On 15 July 2015 at 06:12, Ben Pfaff <blp at nicira.com> wrote:
> On Fri, Jul 10, 2015 at 08:54:03PM +0800, Yousong Zhou wrote:
>> On 8 July 2015 at 21:39, Yousong Zhou <yszhou4tech at gmail.com> wrote:
>> > Hello, list
>> >
>> > I am doing some performance tests for the preparation of upgrading
>> > Open vSwitch from 1.11.0 to 2.3.2.  However, with TCP_CRR, I can only
>> > achieve about 130k tps (last time I got only 40k because of a .debug
>> > type kernel), not even close to the reported 680k from the blog post
>> > [0].  I also found other available reports [1, 2] but those results
>> > were even worse and not consistent with each other.
>> >
>>
>> Hi, I just found the 680k tps TCP_CRR test result in the nsdi2015
>> paper "The design and implementation of Open vSwitch" [1].  Hmm, the
>> 120k tps in section "Cache layer performance" is similar to what I
>> have got.  But how were they boosted to 688k for both Linux bridge and
>> Open vSwitch in section "Comparison to in-kernel switch"?
>
> I think that the configuration we used is described in that paper under
> "Cache layer performance":
>
>     In all following tests, Open vSwitch ran on a Linux server with two
>     8-core, 2.0 GHz Xeon processors and two Intel 10-Gb NICs. To generate
>     many connections, we used Netperf’s TCP CRR test [25], which repeatedly
>     establishes a TCP connection, sends and receives one byte of traffic,
>     and disconnects.  The results are reported in transactions per second
>     (tps).  Netperf only makes one connection attempt at a time, so we ran
>     400 Netperf sessions in parallel and reported the sum.

I already read that part.  The hardware configuration seems to be
comparable [1].  In our tests 32 netperf instances were more or less
enough to get the 130k tps and we increased the number of netperf
pairs to 127 with no obvious improvement.

But when we read that the performance can be as high as 680k with both
Linux bridge and Open vSwitch, we thought there should be something we
overlooked, e.g. system parameters tuning, kernel configuration.

I noticed that in section "Cache layer performance" the best result
was about 120k tps with all optimisations on.  But the result was more
than 680k tps in section "Comparison to in-kernel switch".  How this
boost was done?

Thanks for the reply.

 [1] https://github.com/yousong/brtest/blob/master/out/yousong-X540-AT2.md


Regards

                yousong