An UDP packet is periodically sent from one board to another using a real time thread. The receiving board calculates the intervals between the packets it receives, and sees how much it differs from the scheduled interval.
Two A20 boards are connected end to end with an ethernet cable to a shuttle. All devices are synchronized with PTP. The shuttle sends packets containing timestamps to the boards, and the boards emit a signal at the given timestamp. A logic analyzer measures the variation difference between the signals of the two boards.
**Common test metadata:** Device: A20, Linux kernel version: 5.6, Task priority: 98, Interval: 1000us, Boot Parameters: isolcpus,rcu_nocbs,irqaffinity, ETF qdisc delta: None, Device and processor load: None, Test duration: 0h20, Speed (Mb/s): 1000, ETF offset: 500us, Packet route: E2E, qdisc: pfifo_fast, Client device: A20, XDP: no
Minimum | Maximum | Average | Standard deviation | Lost packets