search

pmonta / GNSS_Firehose

Wideband front-end digitizer for GPS, GLONASS, Galileo, BeiDou
Other
57 stars 35 forks source link

Mac M1 and M2 packets dropping #4

Open AgileEngineeringLLC opened 8 months ago

AgileEngineeringLLC commented 8 months ago

Just a heads-up to others... My Linux boxes work just fine with the Firehose, but both my M1 and M2 macs drop ethernet packets randomly (shows up as IQ values of 0). Appears that the M1 and M2 macs have something wrong in their ethernet firmware or hardware.

pmonta commented 6 months ago

Might there be options in the macOS networking stack or device drivers to help with this? Back in the day I remember playing with things like the Linux driver's RX buffer size or interrupt threshold to decrease drops. Everything has been reliable at default settings of late, though.

By the way, if the dropped packets are single packets only, then the dropout is likely too short in duration to affect the GNSS signal processing. Large contiguous drops, though, of say more than 100 packets in a row, can start to be a problem. Each packet's payload has a timestamp inserted by the FPGA, so the packet2wav tool knows when to fill in with zeros; this means the timing of the sample stream emitted by packet2wav is undisturbed by dropped packets, but of course the SNR decreases because of the lost signal.

AgileEngineeringLLC commented 6 months ago

I researched online and found others having the same issue. I tried several different OS setting changes, but none worked for me. So i gave up trying to use the M2 Mac for recording. The dropped packets were pretty large blocks, and the dropouts occur regularly.