Hi Jeff - I know of no inherent limitation on UDP I/O sizes, but especially at the small payload sizes you note, regardless of OS. I think the best way forward here is to share your flowgraphs with me (off list) & I'll see if I can replicate the issue (I'm still running Mojave, but again I don't think the OS is making the difference here). - MLD
On Fri, Nov 8, 2019 at 6:19 PM Jeff Kyser <ktra...@gmail.com> wrote: > Hi, > > I’m running gnuradio v3.7.13.5 under macOS Catalina. > > We’ve set up transmit and receive flow graphs for a simple BPSK system. > > We pass UDP messages which are received by a UDPSource at the start of the > Rx flow graph, modulation is performed, and the carrier and symbols are > sent to the Tx flow graph via a UDPSink. > > The Tx flow graph receives the data in a UDPSource, performs the > demodulation, and outputs an assembled message from the bytes. > > When I send smaller messages, less than 256 bytes in original length, they > pass through both flow graphs just fine, and we receive exactly what we > sent. > > When I send larger messages, above 256 bytes (actually, they’re about 430 > bytes), they don’t make it out of the UDPSource on the front end of the Rx > flow graph. > > I’ve placed a file sink just before sending the complex data, and one just > after receiving. > > The actual amount of data going across the UDP Sink —> Source is quite > large - a single 180 byte message results in about 700K of complex data. > > But the larger messages never get finished. > > I’ve set the payload size on the UDPSource and UDPSink to 1024, and > there’s been no problem with the smaller messages. > > Is there some kind of buffer overrun going on? When we send the 430 byte > message, it expands to about 1.4 MB of data, which is all captured on the > send side of the interface in the file, but on the receive side, there’s > always only about 1.35 MB, which amounts to about 420 characters. > > Any ideas on this? > > Thank in advance! > > -Jeff > > > -- Michael Dickens Ettus Research Technical Support Email: supp...@ettus.com Web: https://ettus.com/
