Hi Masami,

On Mon, 2018-11-26 at 22:03 +0900, Masami Hiramatsu wrote:

On Wed, 14 Nov 2018 14:18:06 -0600
Tom Zanussi [off-list ref] wrote:

quoted

From: Tom Zanussi <redacted>

Add a test case verifying the basic functionality of the
hist:snapshot() action.

Signed-off-by: Tom Zanussi <redacted>
---
 .../inter-event/trigger-snapshot-action-hist.tc    | 43
++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644
tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-
snapshot-action-hist.tc

diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-

event/trigger-snapshot-action-hist.tc
b/tools/testing/selftests/ftrace/test.d/trigger/inter-
event/trigger-snapshot-action-hist.tc
new file mode 100644
index 000000000000..a0a51e6a6a0c

--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-

event/trigger-snapshot-action-hist.tc

@@ -0,0 +1,43 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test inter-event histogram trigger

snapshot action
+
+fail() { #msg
+    echo $1
+    exit_fail
+}
+
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f snapshot ]; then
+    echo "snapshot is not supported"
+    exit_unsupported
+fi
+
+grep -q "onchange(var)" README > /dev/null || exit_unsupported #
version issue
+
+grep -q "snapshot()" README > /dev/null || exit_unsupported #
version issue

"grep -q ... > /dev/null" is redundant, since -q doesn't show
anything.
please drop "> /dev/null" redirection.

quoted

+
+echo "Test snapshot action"
+
+echo 1 > /sys/kernel/debug/tracing/events/sched/enable
+
+echo
'hist:keys=comm:newprio=prio:onchange($newprio).save(comm,prio):onc
hange($newprio).snapshot() if comm=="ping"' >>
/sys/kernel/debug/tracing/events/sched/sched_waking/trigger

This tests onchange().snapshot(), but document change only describes
onmax().snapshot().
Maybe we should improve document too.

Actually, onchange().snapshot() is documented in '[PATCH v7 11/16]
tracing: Add hist trigger onchange() handler Documentation'.  I can
change the order of the patches if it matters.

Thanks,

Tom