[linux-2.6-block.git] / samples / bpf / tcp_bpf.readme

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
Commit	Line	Data
bfdf7569 LB	1	This file describes how to run the tcp_*_kern.o tcp_bpf (or socket_ops)
	2	programs. These programs attach to a cgroupv2. The following commands create
	3	a 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
ea9b6362	11	Anything that runs under this shell belongs to the foo cgroupv2. To load
bfdf7569 LB	12	(attach) one of the tcp_*_kern.o programs:
bfdf7569 LB	13
ea9b6362 JK	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
bfdf7569	17
ea9b6362 JK	18	"bpftool prog tracelog" will continue to run printing the BPF log buffer.
	19	The tcp_*_kern.o programs use special print functions to print logging
	20	information (if enabled by the ifdef).
bfdf7569 LB	21
	22	If using netperf/netserver to create traffic, you need to run them under the
	23	cgroupv2 to which the BPF programs are attached (i.e. under bash shell
	24	attached to the cgroupv2).
	25
	26	To remove (unattach) a socket_ops BPF program from a cgroupv2:
	27
d78e3f06	28	bpftool cgroup detach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog