This file describes how to run the tcp_*_kern.o tcp_bpf (or socket_ops)
  programs. These programs attach to a cgroupv2. The following commands create
  a cgroupv2 and attach a bash shell to the group.
  
    mkdir -p /tmp/cgroupv2
    mount -t cgroup2 none /tmp/cgroupv2
    mkdir -p /tmp/cgroupv2/foo
    bash
    echo $$ >> /tmp/cgroupv2/foo/cgroup.procs

  Anything that runs under this shell belongs to the foo cgroupv2. To load

  (attach) one of the tcp_*_kern.o programs:

    bpftool prog load tcp_basertt_kern.o /sys/fs/bpf/tcp_prog
    bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog
    bpftool prog tracelog

  "bpftool prog tracelog" will continue to run printing the BPF log buffer.
  The tcp_*_kern.o programs use special print functions to print logging
  information (if enabled by the ifdef).

  
  If using netperf/netserver to create traffic, you need to run them under the
  cgroupv2 to which the BPF programs are attached (i.e. under bash shell
  attached to the cgroupv2).
  
  To remove (unattach) a socket_ops BPF program from a cgroupv2:

    bpftool cgroup detach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog