UDP Throughput Intermittentcy/Transience

[Colonel1013]

Current Versions of Software:

LabVIEW 2014 SP1

Hi all, I am planning on creating a layer of a LabVIEW application where I will interface with external software via UDP.

I wrote a benchmarking utility (see the attached VIs) to see HOW fast I can go (attached are the VI's, there's a Sender VI and a Receiver VI, and I played with the receive buffer as well, which is also included in a VI)

I plan on doing a few benchmarks, and one of them entails how fast I can send data within the same PC (so no network cards, no LAN cables, just external software sending data to this application on the same PC via UDP)

The benchmarking VIs (I hacked the example UDP send) can modify the message length, and send and receiver message send times, and measures throughput by dividing the length of the messages received by the times it received them.

My initial tests for sending UDP data within the PC give me throughputs with trends I'd like to get to the bottom of....

I set my read and write sizes to the maximum I can for UDP (65507), and when I start the read vi, my throughputs start at a lower rate, then settle to a higher rate (at around 200 MB/sec).

Below is a graph showing two runs, where they start lower, then reach a higher throughput.

Any ideas on why this is happening?

Also, any ideas on ways I can increase my throughput to be higher?

Thanks

[WireWeaver]

Hi Colonel,

I got an access violation error when I opened those VI's. It looks like you've altered some functions that aren't meant to be changed.

You could analyze both programs with Wireshark to see what you are really sending/getting. Also, try slowing down your loop rate to see if you still get the same behavior. It may take your data longer to read/write than the wait set in the loop.

[Intaris]

I wouldn't be so sure that your network card isn't involved.

UDP is a broadcast protocol, so your sender probably IS sending actual packets via your network card.  It's not a point-to-point connection like TCP.

Maybe someone else could give more insight, but the claim that the network card is not involved needs closer inspection.  This might explain your speed limit.