Re: [PATCH 0/2] tracing/triggers: A couple minor variable name changes

[Steven Rostedt <rostedt@goodmis.org>]

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On Mon, 06 Jan 2014 20:51:09 -0600
Tom Zanussi <tom.zanussi@linux.intel.com> wrote:

> I'll run the next version through my 'testsuite', which unfortunately is
> still manual (one of the many things on my todo list is automate it)..

I have some basic tests, attached is one. Which failed. Here's the
patch that fixes it:

-- Steve

tracing: Fix counter for traceon/off event triggers

The counters for the traceon and traceoff are only suppose to decrement
when the trigger enables or disables tracing. It is not suppose to decrement
every time the event is hit.

Only decrement the counter if the trigger actually did something.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events_trigger.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index f6dd115..a53e0da 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -742,13 +742,16 @@ traceon_trigger(struct event_trigger_data *data)
 static void
 traceon_count_trigger(struct event_trigger_data *data)
 {
+	if (tracing_is_on())
+		return;
+
 	if (!data->count)
 		return;
 
 	if (data->count != -1)
 		(data->count)--;
 
-	traceon_trigger(data);
+	tracing_on();
 }
 
 static void
@@ -763,13 +766,16 @@ traceoff_trigger(struct event_trigger_data *data)
 static void
 traceoff_count_trigger(struct event_trigger_data *data)
 {
+	if (!tracing_is_on())
+		return;
+
 	if (!data->count)
 		return;
 
 	if (data->count != -1)
 		(data->count)--;
 
-	traceoff_trigger(data);
+	tracing_off();
 }
 
 static int
-- 
1.8.1.4



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#!/bin/bash

find_debugfs() {
    debugfs=`cat /proc/mounts | while read mount dir type opts a b; do
	if [ $mount == "debugfs" ]; then
	    echo $dir;
	    break
	fi
    done`
    if [ -z "$debugfs" ]; then
	if ! mount -t debugfs nodev /sys/kernel/debug; then
	    echo "FAILED to mount debugfs"
	    exit -1
	fi
	echo "/sys/kernel/debug"
    else
	echo $debugfs
    fi
}

debugfs=`find_debugfs`
TRACEDIR="$debugfs/tracing"
EVENTDIR=$TRACEDIR/events

if [ ! -f $EVENTDIR/sched/sched_switch/trigger ]; then
    echo "triggers are not set for this kernel"
    exit 0
fi

function cnt_trace() {
	    grep -v '^#' $TRACEDIR/trace | wc -l
}

function check_traceon() {
    val=$1
    cur=`cat $TRACEDIR/tracing_on`
    if [ $val -ne $cur ]; then
	echo "traceon expected to be $val but was $cur"
	exit 1
    fi
}

set -x
      
echo '** DISABLE TRACING'
echo 0 > $TRACEDIR/tracing_on || exit -1
echo > $TRACEDIR/trace || exit -1

check_traceon 0

cnt=`cnt_trace`
if [ $cnt -ne 0 ]; then
   exit -1
fi


echo '** ENABLE FUNCTION TRACING'

echo function > $TRACEDIR/current_tracer || exit -1

echo '** ENABLE TRACING'
echo 1 > $TRACEDIR/tracing_on || exit -1

cnt=`cnt_trace`
if [ $cnt -eq 0 ]; then
   exit -1
fi

echo '** SET EVENT TRACEOFF'

check_traceon 1

echo "traceoff" > $EVENTDIR/sched/sched_switch/trigger
sleep 1
check_traceon 0
cnt=`cnt_trace`
sleep 1
cnt2=`cnt_trace`

if [ $cnt -ne $cnt2 ]; then
   exit -1;
fi

line1=`cat $TRACEDIR/trace | tail -1`
sleep 1
line2=`cat $TRACEDIR/trace | tail -1`

if [ $line1 != $line2 ]; then
   exit -1
fi

echo > $TRACEDIR/trace || exit -1

check_traceon 0

echo "!traceoff" >> $EVENTDIR/sched/sched_switch/trigger

check_traceon 0

echo "traceon" >> $EVENTDIR/sched/sched_switch/trigger

sleep 1

cnt=`cnt_trace`
if [ $cnt -eq 0 ]; then
   exit -1
fi

check_traceon 1


echo "!traceon" >> $EVENTDIR/sched/sched_switch/trigger

check_sleep() {
    val=$1
    sleep 1
    check_traceon $val
}

echo '** TEST COUNT traceoff (3)'

echo "traceoff:3" >> $EVENTDIR/sched/sched_switch/trigger
check_sleep "0"
echo '** TEST COUNT traceoff (2)'
echo 1 > $TRACEDIR/tracing_on
check_sleep "0"
echo '** TEST COUNT traceoff (1)'
echo 1 > $TRACEDIR/tracing_on
check_sleep "0"
echo '** TEST COUNT traceoff (0)'
echo 1 > $TRACEDIR/tracing_on
check_sleep "1"
echo "!traceoff:0" >> $EVENTDIR/sched/sched_switch/trigger

echo nop > $TRACEDIR/current_tracer

echo '** SUCCESS'

exit 0