[tip:perf/core] perf test shell: Add test using probe:vfs_getname and verifying results

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  6060c7264ded3f6fa17e74bca3e192ce477e8063
Gitweb:     http://git.kernel.org/tip/6060c7264ded3f6fa17e74bca3e192ce477e8063
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Fri, 4 Aug 2017 14:39:37 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 11 Aug 2017 16:06:30 -0300

perf test shell: Add test using probe:vfs_getname and verifying results

This test uses the 'perf test shell' library to add probe:vfs_getname to the
system then use it with 'perf record' using 'touch' to write to a temp file,
then checks that that was captured by the vfs_getname probe in the generated
perf.data file, with the temp file name as the pathname argument.

Using it:

  # perf test "Use vfs_getname"
  60: Use vfs_getname probe to get syscall args filenames: Ok
  # perf test -v "Use vfs_getname"
  60: Use vfs_getname probe to get syscall args filenames:
  --- start ---
  test child forked, pid 16414
  Added new event:
    probe:vfs_getname    (on getname_flags:72 with pathname=result->name:string)

  You can now use it in all perf tools, such as:

	perf record -e probe:vfs_getname -aR sleep 1

  Recording open file:
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.022 MB /tmp/vaca.perf.data.QZsn7 (13 samples) ]
  Looking at perf.data file for vfs_getname records for the file we touched:
             touch 16421 [002] 1255152.879561: probe:vfs_getname: (ffffffffa626e608) pathname="/tmp/vaca.l10SL"
  test child finished with 0
  ---- end ----
  Use vfs_getname probe to get syscall args filenames: Ok
  #

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Michael Petlan <mpetlan@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-t555fnhbcbxnukltk23dqxur@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 .../tests/shell/record+script_probe_vfs_getname.sh | 37 ++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/tools/perf/tests/shell/record+script_probe_vfs_getname.sh b/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
new file mode 100755
index 0000000..2725c5d
--- /dev/null
+++ b/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
@@ -0,0 +1,37 @@
+# Use vfs_getname probe to get syscall args filenames
+
+# Uses the 'perf test shell' library to add probe:vfs_getname to the system
+# then use it with 'perf record' using 'touch' to write to a temp file, then
+# checks that that was captured by the vfs_getname probe in the generated
+# perf.data file, with the temp file name as the pathname argument.
+
+# Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>, 2017
+
+. $(dirname $0)/lib/probe_vfs_getname.sh
+
+perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+file=$(mktemp /tmp/temporary_file.XXXXX)
+
+record_open_file() {
+	echo "Recording open 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=\"${file}\""
+}
+
+add_probe_vfs_getname || skip_if_no_debuginfo
+err=$?
+if [ $err -ne 0 ] ; then
+	exit $err
+fi
+
+record_open_file && perf_script_filenames
+err=$?
+rm -f ${perfdata}
+rm -f ${file}
+cleanup_probe_vfs_getname
+exit $err