A smol ๐ค static rust binary which can be used to surface kernel queueing metrics with eBPF kprobes.
The easiest metrics to surface are anything found in the sock API.
The following 'accept queues' are currently instrumented.
- TCP/IPv4
- TCP/IPv6
- UDP (Connectionless)
- Unix domain
# Compile the eBPF probe, embed the probe into the binary, compile and install the static binary
make ebpf install
sudo q
Execute the dysfunctional-listen-not-accept-tcp-exec
server and send curl requests to localhost:9064
.
Notice that the requests will accumulate in the accept queue even once the client has been killed. The only way to "flush" the queue is to terminate the server. I am currently unsure if Linux provides another way to clean up these orphaned connections.
[2023-03-13T04:50:35Z INFO q] Success! Loaded eBPF probe into kernel
[2023-03-13T04:50:35Z INFO q] --> Attached: kprobe__tcp_conn_request
[2023-03-13T04:50:35Z INFO q] --> Attached: kprobe__inet_csk_accept
[2023-03-13T04:50:35Z INFO q] Waiting for Ctrl-C...
[2023-03-13T04:50:44Z INFO qprobe] AF_INET 'accept queue' qlen: 8, qmax: 4096, src address: 0.0.0.0, dest address: 0.0.0.0
[2023-03-13T04:50:48Z INFO qprobe] AF_INET 'accept queue' qlen: 9, qmax: 4096, src address: 0.0.0.0, dest address: 0.0.0.0
[2023-03-13T04:50:50Z INFO qprobe] AF_INET 'accept queue' qlen: 10, qmax: 4096, src address: 0.0.0.0, dest address: 0.0.0.0
[2023-03-13T04:50:51Z INFO qprobe] AF_INET 'accept queue' qlen: 11, qmax: 4096, src address: 0.0.0.0, dest address: 0.0.0.0