When I run top -p <pid> command, I can see that process is using about 10% of cpu but when I press "H" to list threads, cpu usage of each of the thread is shown as 0%.
Why is that so? I want to see Java threads CPU usage in realtime, is top not the best way?
Screenshots (before pressing H)
After pressing H-
If you prefer to work with a script like tool there is also jvmtop that gives you the cpu usage per thread.
Sample output bellow.
You can use jconsole if you are using the Sun Java JDK Distribution. It is built in as part of the bundle from Java 1.5 onwards if I am not mistaken. You can see Threads, Classes loaded, Memory Usage and CPU Usage of JVMs in real time.
Java 1.6 and above version have inbuild java tools for monitoring / debugging java modules. Here isthe below sample script : ` #/bin/bash
#Initilization of variable
CUREENT_DATE=`date -d "0 day" "+%Y%m%d"` #2012-06-22
CURRENT_MONTH=`date -d "0 month" "+%B%Y"` #June2012
LAST_DATE=`date -d "1 day ago" "+%Y%m%d"` #2012-06-21
BASE_PATH="/home/javaMonitoring"
SCRIPT_LOGS="/home/javaMonitoring/logs"
JAVA_PATH=`echo $JAVA_HOME`
PERM=0
MSG="No Message"
HOSTIP="localhost"
THRESHOLD=80;
if [ ! -d $BASE_PATH ];then
echo " Base Directory not exists![$BASE_PATH]"
exit
fi
cd $BASE_PATH
if [ ! -d $SCRIPT_LOGS ];then
echo " Log Directory note found [$SCRIPT_LOGS]"
mkdir -p $SCRIPT_LOGS
fi
##LOG Directory
if [ ! -d $CUREENT_DATE ];then
echo " Log Directory note found [$CUREENT_DATE]"
mkdir -p $CUREENT_DATE
fi
log_file_path="$SCRIPT_LOGS/${CUREENT_DATE}-"`basename $0 .sh`".log"
echo "############ Script:$log_file_path##################" >$log_file_path
#####Funcations
cd $JAVA_PATH/bin
BOOTSTRAP=`${JAVA_PATH}/bin/jps|grep Bootstrap|cut -d " " -f1`
if [ $? -ne 0 ];then
echo "No Bootstrap PID exists[${JAVA_PATH}/bin/jps|grep Bootstrap]" >>$log_file_path
exit
#If log file not exists
else
if [ ! -f ${BASE_PATH}/${CUREENT_DATE}/gcutil.txt ];then
touch ${BASE_PATH}/${CUREENT_DATE}/gcutil.txt
echo "Timestamp S0 S1 E O P YGC YGCT FGC FGCT GCT" > ${BASE_PATH}/${CUREENT_DATE}/gcutil.txt
fi
./jstat -gcutil -t $BOOTSTRAP|grep -v Timestamp >> ${BASE_PATH}/${CUREENT_DATE}/gcutil.txt
PERM=`jstat -gcutil -t ${BOOTSTRAP} | grep -v Timestamp|awk -F " " '{print $6}'`
#if [ ${PERM} -ge ${THRESHOLD} ];then
if [ $PERM > $THRESHOLD ];then
MSG="MCOM: Alert `date` on ${HOSTIP} Server Current Perm is :: ${PERM}%"
fi
#continue;
fi `
OUTPUT save in :: ../YYYYMMDD/gcutil.txt
Timestamp S0 S1 E O P YGC YGCT FGC FGCT GCT
16193.4 0.00 59.95 55.13 93.86 89.63 226 26.192 41 48.532 74.724
16196.5 0.00 59.95 55.14 93.86 89.63 226 26.192 41 48.532 74.724
