Commit 194cb6b5 authored Jul 22, 2020 by Michael Petlan Committed by Arnaldo Carvalho de Melo Aug 13, 2020

perf test: Allow multiple probes in record+script_probe_vfs_getname.sh



Sometimes when adding a kprobe by perf, it results in multiple probe
points, such as the following:

  # ./perf probe -l
    probe:vfs_getname    (on getname_flags:73@fs/namei.c with pathname)
    probe:vfs_getname_1  (on getname_flags:73@fs/namei.c with pathname)
    probe:vfs_getname_2  (on getname_flags:73@fs/namei.c with pathname)
  # cat /sys/kernel/debug/tracing/kprobe_events
  p:probe/vfs_getname _text+5501804 pathname=+0(+0(%gpr31)):string
  p:probe/vfs_getname_1 _text+5505388 pathname=+0(+0(%gpr31)):string
  p:probe/vfs_getname_2 _text+5508396 pathname=+0(+0(%gpr31)):string

In this test, we need to record all of them and expect any of them in
the perf-script output, since it's not clear which one will be used for
the desired syscall:

  # perf stat -e probe:vfs_getname\* -- touch /tmp/nic

   Performance counter stats for 'touch /tmp/nic':

                31      probe:vfs_getname_2
                 0      probe:vfs_getname_1
                 1      probe:vfs_getname
       0.001421826 seconds time elapsed

       0.001506000 seconds user
       0.000000000 seconds sys

If the test relies only on probe:vfs_getname, it might easily miss the
relevant data.

Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
LPU-Reference: 20200722135845.29958-1-mpetlan@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 1beaef29

tools/perf/tests/shell/record+script_probe_vfs_getname.sh

+2 −2

Original line number	Diff line number	Diff line
		@@ -20,13 +20,13 @@ file=$(mktemp /tmp/temporary_file.XXXXX)

		record_open_file() {
		echo "Recording open file:"
		perf record -o ${perfdata} -e probe:vfs_getname touch $file
		perf record -o ${perfdata} -e probe:vfs_getname\* touch $file
		}

		perf_script_filenames() {
		echo "Looking at perf.data file for vfs_getname records for the file we touched:"
		perf script -i ${perfdata} \| \
		egrep " +touch +[0-9]+ +\[[0-9]+\] +[0-9]+\.[0-9]+: +probe:vfs_getname: +$[[:xdigit:]]+$ +pathname=\"${file}\""
		egrep " +touch +[0-9]+ +\[[0-9]+\] +[0-9]+\.[0-9]+: +probe:vfs_getname[_0-9]*: +$[[:xdigit:]]+$ +pathname=\"${file}\""
		}

		add_probe_vfs_getname \|\| skip_if_no_debuginfo

Admin message