ftracetest: Do not use usleep directly

The usleep is only provided on distros from Redhat so running ftracetest
on other distro resulted in failures due to the missing usleep.

The reason of using [u]sleep in the test was to generate (scheduler)
events.  It can be done various ways like this:

yield() {  ping localhost -c 1 || sleep .001 || usleep 1 || sleep 1; }

For more information to the history of this patch, please refer to:

Link: http://lkml.kernel.org/r/1427329943-16896-1-git-send-email-namhyung@kernel.org

Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Reported-by: Luis Henriques <luis.henriques@canonical.com>
Suggested-by: Pádraig Brady <P@draigBrady.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/ftrace/test.d/event/event-enable.tc

@@ -12,6 +12,10 @@ fail() { #msg
     exit $FAIL
 }
 
+yield() {
+    ping localhost -c 1 || sleep .001 || usleep 1 || sleep 1
+}
+
 if [ ! -f set_event -o ! -d events/sched ]; then
     echo "event tracing is not supported"
     exit_unsupported
@@ -21,7 +25,8 @@ reset_tracer
 do_reset
 
 echo 'sched:sched_switch' > set_event
-usleep 1
+
+yield
 
 count=`cat trace | grep sched_switch | wc -l`
 if [ $count -eq 0 ]; then
@@ -31,7 +36,8 @@ fi
 do_reset
 
 echo 1 > events/sched/sched_switch/enable
-usleep 1
+
+yield
 
 count=`cat trace | grep sched_switch | wc -l`
 if [ $count -eq 0 ]; then
@@ -41,7 +47,8 @@ fi
 do_reset
 
 echo 0 > events/sched/sched_switch/enable
-usleep 1
+
+yield
 
 count=`cat trace | grep sched_switch | wc -l`
 if [ $count -ne 0 ]; then

tools/testing/selftests/ftrace/test.d/event/subsystem-enable.tc

@@ -12,6 +12,10 @@ fail() { #msg
     exit $FAIL
 }
 
+yield() {
+    ping localhost -c 1 || sleep .001 || usleep 1 || sleep 1
+}
+
 if [ ! -f set_event -o ! -d events/sched ]; then
     echo "event tracing is not supported"
     exit_unsupported
@@ -21,7 +25,8 @@ reset_tracer
 do_reset
 
 echo 'sched:*' > set_event
-usleep 1
+
+yield
 
 count=`cat trace | grep -v ^# | awk '{ print $5 }' | sort -u | wc -l`
 if [ $count -lt 3 ]; then
@@ -31,7 +36,8 @@ fi
 do_reset
 
 echo 1 > events/sched/enable
-usleep 1
+
+yield
 
 count=`cat trace | grep -v ^# | awk '{ print $5 }' | sort -u | wc -l`
 if [ $count -lt 3 ]; then
@@ -41,7 +47,8 @@ fi
 do_reset
 
 echo 0 > events/sched/enable
-usleep 1
+
+yield
 
 count=`cat trace | grep -v ^# | awk '{ print $5 }' | sort -u | wc -l`
 if [ $count -ne 0 ]; then

tools/testing/selftests/ftrace/test.d/event/toplevel-enable.tc

@@ -12,6 +12,10 @@ fail() { #msg
     exit $FAIL
 }
 
+yield() {
+    ping localhost -c 1 || sleep .001 || usleep 1 || sleep 1
+}
+
 if [ ! -f available_events -o ! -f set_event -o ! -d events ]; then
     echo "event tracing is not supported"
     exit_unsupported
@@ -21,6 +25,9 @@ reset_tracer
 do_reset
 
 echo '*:*' > set_event
+
+yield
+
 count=`cat trace | grep -v ^# | wc -l`
 if [ $count -eq 0 ]; then
     fail "none of events are recorded"
@@ -29,6 +36,9 @@ fi
 do_reset
 
 echo 1 > events/enable
+
+yield
+
 count=`cat trace | grep -v ^# | wc -l`
 if [ $count -eq 0 ]; then
     fail "none of events are recorded"
@@ -37,6 +47,9 @@ fi
 do_reset
 
 echo 0 > events/enable
+
+yield
+
 count=`cat trace | grep -v ^# | wc -l`
 if [ $count -ne 0 ]; then
     fail "any of events should not be recorded"