linux-stable/samples/bpf/lwt_len_hist.sh
Ross Zwisler 27d7fdf06f bpf: use canonical ftrace path
The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

  Before 4.1, all ftrace tracing control files were within the debugfs
  file system, which is typically located at /sys/kernel/debug/tracing.
  For backward compatibility, when mounting the debugfs file system,
  the tracefs file system will be automatically mounted at:

  /sys/kernel/debug/tracing

Many comments and samples in the bpf code still refer to this older
debugfs path, so let's update them to avoid confusion.  There are a few
spots where the bpf code explicitly checks both tracefs and debugfs
(tools/bpf/bpftool/tracelog.c and tools/lib/api/fs/fs.c) and I've left
those alone so that the tools can continue to work with both paths.

Signed-off-by: Ross Zwisler <zwisler@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230313205628.1058720-2-zwisler@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-13 21:51:30 -07:00

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Executable file

#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
NS1=lwt_ns1
VETH0=tst_lwt1a
VETH1=tst_lwt1b
BPF_PROG=lwt_len_hist.bpf.o
TRACE_ROOT=/sys/kernel/tracing
function cleanup {
# To reset saved histogram, remove pinned map
rm /sys/fs/bpf/tc/globals/lwt_len_hist_map
ip route del 192.168.253.2/32 dev $VETH0 2> /dev/null
ip link del $VETH0 2> /dev/null
ip link del $VETH1 2> /dev/null
ip netns exec $NS1 killall netserver
ip netns delete $NS1 2> /dev/null
}
cleanup
ip netns add $NS1
ip link add $VETH0 type veth peer name $VETH1
ip link set dev $VETH0 up
ip addr add 192.168.253.1/24 dev $VETH0
ip link set $VETH1 netns $NS1
ip netns exec $NS1 ip link set dev $VETH1 up
ip netns exec $NS1 ip addr add 192.168.253.2/24 dev $VETH1
ip netns exec $NS1 netserver
echo 1 > ${TRACE_ROOT}/tracing_on
cp /dev/null ${TRACE_ROOT}/trace
ip route add 192.168.253.2/32 encap bpf out obj $BPF_PROG section len_hist dev $VETH0
netperf -H 192.168.253.2 -t TCP_STREAM
cat ${TRACE_ROOT}/trace | grep -v '^#'
./lwt_len_hist
cleanup
echo 0 > ${TRACE_ROOT}/tracing_on
exit 0