1This file describes how to run the tcp_*_kern.o tcp_bpf (or socket_ops)
2programs. These programs attach to a cgroupv2. The following commands create
3a cgroupv2 and attach a bash shell to the group.
4
5  mkdir -p /tmp/cgroupv2
6  mount -t cgroup2 none /tmp/cgroupv2
7  mkdir -p /tmp/cgroupv2/foo
8  bash
9  echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
10
11Anything that runs under this shell belongs to the foo cgroupv2. To load
12(attach) one of the tcp_*_kern.o programs:
13
14  bpftool prog load tcp_basertt_kern.o /sys/fs/bpf/tcp_prog
15  bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog
16  bpftool prog tracelog
17
18"bpftool prog tracelog" will continue to run printing the BPF log buffer.
19The tcp_*_kern.o programs use special print functions to print logging
20information (if enabled by the ifdef).
21
22If using netperf/netserver to create traffic, you need to run them under the
23cgroupv2 to which the BPF programs are attached (i.e. under bash shell
24attached to the cgroupv2).
25
26To remove (unattach) a socket_ops BPF program from a cgroupv2:
27
28  bpftool cgroup detach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog
29