To monitor UDP latency using eBPF, you can write a program that traces UDP packets and measures the time taken for packets to travel between specific points in the network stack. Here’s a basic example of an eBPF program to monitor UDP latency:
This eBPF program traces UDP packets and calculates the latency between when a UDP packet is received and when it is sent. Here’s a breakdown of what the program does:
It defines two hash maps (start and udp_events) to store the start time of packet processing and the calculated latencies, respectively.
In the udp_latency function, it first retrieves the process ID (pid) of the current packet.
It then checks if the packet is UDP by inspecting the Ethernet and IP headers.
If the packet is UDP, it calculates the latency by subtracting the start time stored in the start map from the current time (ts).
It updates the udp_events map with the calculated latency.
Finally, it deletes the entry from the start map.
You can compile this eBPF program using the BPF Compiler Collection (BCC) and attach it to a network interface to start monitoring UDP latency. Remember to also write a userspace program to read and display the latency data collected by the eBPF program.
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