p2020 tcp throughput

[parkmanchan]

Hi folks,

  What would be the expected TCP throughput on a P2020?

  I'm getting a Rx/Tx bandwidth of around 850Mbits/s when testing Rx/Tx separately, but when testing  Rx/Tx at the same time, the Rx throughput drops to less than 300Mbits/s, with Tx at around 800Mbits/s. What could be the problem here? Is this limited by the CPU?

Details of the test setup.

   PC1  -> P2020 eth0 -> PC2

   P2020 running Linux 2.6.35, TCP bandwidth testing with iperf 2.0.5

1. Rx bandwidth

    on the P2020

          iperf -s

    PC1

          iperf -c P2020_ip

2. Tx bandwidth

    on the P2020

          iperf -c PC2_ip

    PC2

          iperf -s

3. Runs 1 and 2 at the same time for testing Rx/Tx at the same time.

Thanks.

[yipingwang · Accepted solution]

Hello Park man Chan,

Since you are using the old version Linux 2.6.35, the throughput should be a little lower than the expected result, with the latest SDK, the throughput is much better than your result. Not sure what is your testing frame size, because larger frame gets better throughput.

For the behavior Rx throughput dropping much than Tx, this should be normal, because for netperf(iperf) testing, the bottleneck is CPU.

Have a great day,
Yiping

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