[PATCH v2] perf test: Adapt test case record+probe_libc_inet_pton.sh for s390

From: Thomas Richter
Date: Mon Apr 23 2018 - 04:24:53 EST

perf test case 58 (record+probe_libc_inet_pton.sh)
executed on s390x using kernel 4.16.0rc3
displays this result:
# ./perf trace --no-syscalls
-e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
probe_libc:inet_pton: (3ffa0240448)
__GI___inet_pton (/usr/lib64/libc-2.26.so)
gaih_inet (inlined)
__GI_getaddrinfo (inlined)
main (/usr/bin/ping)
__libc_start_main (/usr/lib64/libc-2.26.so)
_start (/usr/bin/ping)

After I installed kernel 4.16.0 the same tests uses
# perf record -e probe_libc:inet_pton/call-graph=dwarf/
-o /tmp/perf.data.abc ping -6 -c 1 ::1
# perf script -i /tmp/perf.data.abc
and displays:
ping 39048 [006] 84230.381198: probe_libc:inet_pton: (3ffa0240448)
140448 __GI___inet_pton (/usr/lib64/libc-2.26.so)
fbde1 gaih_inet (inlined)
fe2b9 __GI_getaddrinfo (inlined)
398d main (/usr/bin/ping)

Nothing else changed including glibc elfutils and other libraries
picked up by the build.
The entries for __libc_start_main and _start are missing.

I bisected missing __libc_start_main and _start to commit
("perf unwind: Unwind with libdw doesn't take symfs into account")

When I undo this commit I get this call stack on s390:
[root@s35lp76 perf]# ./perf script -i /tmp/perf.data.abc
ping 39048 [006] 84230.381198: probe_libc:inet_pton: (3ffa0240448)
140448 __GI___inet_pton (/usr/lib64/libc-2.26.so)
fbde1 gaih_inet (inlined)
fe2b9 __GI_getaddrinfo (inlined)
398d main (/usr/bin/ping)
22fbd __libc_start_main (/usr/lib64/libc-2.26.so)
457b _start (/usr/bin/ping)

Looks like dwarf functions dwfl_xxx create different call back
stack trace when using file
/usr/lib/debug/usr/bin/ping-20161105-7.fc27.s390x.debug instead of
file /usr/bin/ping.

Fix this test case on s390 and do not expect any call back stack
entry after the main() function. Also be more robust and accept a
leading __GI_ prefix in front of getaddrinfo.

On x86 this test case shows the same call stack using
both kernel versions 4.16.0rc3 and 4.16.0 and also
stops at main:

[root@f27 perf]# ./perf script -i /tmp/perf.data.tmr
ping 4446 [000] 172.027088: probe_libc:inet_pton: (7fdfa08c93c0)
1393c0 __GI___inet_pton (/usr/lib64/libc-2.26.so)
fe60d getaddrinfo (/usr/lib64/libc-2.26.so)
2f40 main (/usr/bin/ping)

[root@f27 perf]#

Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Reviewed-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxx>
tools/perf/tests/shell/record+probe_libc_inet_pton.sh | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
index 1ecc1f0ff84a..016882dbbc16 100755
--- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
+++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
@@ -19,12 +19,10 @@ trace_libc_inet_pton_backtrace() {
case "$(uname -m)" in
- eventattr='call-graph=dwarf'
+ eventattr='call-graph=dwarf,max-stack=4'
- expected[3]="__GI_getaddrinfo[[:space:]]\($libc|inlined\)$"
+ expected[3]="(__GI_)?getaddrinfo[[:space:]]\($libc|inlined\)$"
- expected[5]="__libc_start_main[[:space:]]\($libc\)$"
- expected[6]="_start[[:space:]]\(.*/bin/ping.*\)$"