perfSONAR User Q&A and Other Discussion

[Jason Zurawski <>]

Greetings;

Besides the end hosts being configured for Jumbo frames, the entire broadcast domain needs to be working with jumbo frames as well (e.g. the switch, and devices populating it).  If something is mis-configured, the application will not function.  You can test to be sure you have a clean 9000 byte path with 'ping -s 8972'. 

Thanks;

-jason

Xu Chen wrote:

Their MTU size is also 9000.

On Sep 24, 2015, at 2:35 PM, Brian Jones <> wrote:

You may want to check the testing end point sides mtu size.

fwiw

--
Brian

On Thu, Sep 24, 2015 at 2:26 PM, Xu Chen <> wrote:

Hello all,

I use 10G NIC on my perfSONAR node. When I start a tcp throughput test from my node to another node, the throughput is 1.2 Gbps (before I use 10G NIC, it’s 911Mbps). After I reserve the the source and destination, the result becomes 0.4 Gbps. I use default TCP window size and MTU is 1500.  What do I miss on the configuration (perfSONAR toolkit or NIC)?

Another problem is when I change MTU from 1500 to 9000 (ifconfig eth0 mtu 9000 up), I met the following problem when starting a test.

bwctl: Using tool: iperf

bwctl: 26 seconds until test results available

RECEIVER START

------------------------------------------------------------

Server listening on TCP port 5191

Binding to local address 140.221.68.2

TCP window size: 87380 Byte (default)

------------------------------------------------------------

[ 15] local 140.221.68.2 port 5191 connected with 129.63.79.200 port 47521

Waiting for server threads to complete. Interrupt again to force quit.

bwctl: local tool did not complete in allocated time frame and was killed

What should I do so that I can use jumbo frame?

Thanks,

Chen Xu