linux-kernel - [PATCH v2] selftests/ftrace: Use /bin/echo instead of built-in echo

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Message-Id: <158894782360.14326.6909620051395004844.stgit@devnote2>
Date:   Fri,  8 May 2020 23:23:43 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Shuah Khan <shuah@...nel.org>, Steven Rostedt <rostedt@...dmis.org>
Cc:     linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tom Zanussi <tom.zanussi@...ux.intel.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Li Philip <philip.li@...el.com>,
        Liu Yiding <yidingx.liu@...el.com>,
        Xiao Yang <yangx.jy@...fujitsu.com>
Subject: [PATCH v2] selftests/ftrace: Use /bin/echo instead of built-in echo

Since the built-in echo has different behavior in POSIX shell
(dash) and bash, we forcibly use /bin/echo -E (not interpret
backslash escapes) by default.

This also fixes some test cases which expects built-in
echo command since the built-in echo command will share
the same pid with the shell.

trigger-trace-marker-hist.tc and trigger-trace-marker-synthetic.tc
write trace_marker several times to make a histogram with the pid
as the key. If we use /bin/echo command, the pid-key is different
each time and failed to make a histogram. This changes those test
to use "ip" (called address) as a key which should be always same
if trace_marker is used.

For trigger-trace-marker-synthetic-kernel.tc, this uses built-in
echo as a special case, because the test case is based on the
wakeup event and the trace_marker event and uses the pid as
common-key for those events. In this case, we must use built-in
echo to make a short "sleep, wakeup and write" program.

Reported-by: Liu Yiding <yidingx.liu@...el.com>
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
Reviewed-by: Tom Zanussi <tom.zanussi@...ux.intel.com>
---
 Changes in v2:
  - Add descriptions for some test-case fixes.
---
 tools/testing/selftests/ftrace/test.d/functions    |    4 ++++
 .../test.d/trigger/trigger-trace-marker-hist.tc    |    2 +-
 .../trigger-trace-marker-synthetic-kernel.tc       |    4 ++++
 .../trigger/trigger-trace-marker-synthetic.tc      |    4 ++--
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
index 61a3c7e2634d..0ff92aa12e2a 100644
--- a/tools/testing/selftests/ftrace/test.d/functions
+++ b/tools/testing/selftests/ftrace/test.d/functions
@@ -1,3 +1,7 @@
+# Since the built-in echo has different behavior in POSIX shell (dash) and
+# bash, we forcibly use /bin/echo -E (not interpret backslash escapes).
+alias echo="/bin/echo -E"
+
 check_filter_file() { # check filter file introduced by dynamic ftrace
     if [ ! -f "$1" ]; then
         echo "$1 not found? Is dynamic ftrace not set?"
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc
index ab6bedb25736..b3f70f53ee69 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc
@@ -30,7 +30,7 @@ fi
 
 echo "Test histogram trace_marker tigger"
 
-echo 'hist:keys=common_pid' > events/ftrace/print/trigger
+echo 'hist:keys=ip' > events/ftrace/print/trigger
 for i in `seq 1 10` ; do echo "hello" > trace_marker; done
 grep 'hitcount: *10$' events/ftrace/print/hist > /dev/null || \
     fail "hist trigger did not trigger correct times on trace_marker"
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc
index 18b4d1c2807e..c1625d945f4d 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc
@@ -44,6 +44,10 @@ echo 'latency u64 lat' > synthetic_events
 echo 'hist:keys=pid:ts0=common_timestamp.usecs' > events/sched/sched_waking/trigger
 echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).latency($lat)' > events/ftrace/print/trigger
 echo 'hist:keys=common_pid,lat:sort=lat' > events/synthetic/latency/trigger
+
+# We have to use the built-in echo here because waking up pid must be same
+# as echoing pid.
+alias echo=echo
 sleep 1
 echo "hello" > trace_marker
 
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
index dd262d6d0db6..23e52c8d71de 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
@@ -36,8 +36,8 @@ fi
 echo "Test histogram trace_marker to trace_marker latency histogram trigger"
 
 echo 'latency u64 lat' > synthetic_events
-echo 'hist:keys=common_pid:ts0=common_timestamp.usecs if buf == "start"' > events/ftrace/print/trigger
-echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"' >> events/ftrace/print/trigger
+echo 'hist:keys=ip:ts0=common_timestamp.usecs if buf == "start"' > events/ftrace/print/trigger
+echo 'hist:keys=ip:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"' >> events/ftrace/print/trigger
 echo 'hist:keys=common_pid,lat:sort=lat' > events/synthetic/latency/trigger
 echo -n "start" > trace_marker
 echo -n "end" > trace_marker