【JVM性能调优】检测最耗cpu的线程的脚本

经常定位线程对cpu的耗时情况，每次重复去输入命令很不方便，特别写了一个脚本用于快速打印jvm的线程耗时情况

#!/bin/bash

if [ $# -eq 0 ];then
  echo "please enter java pid"
  exit -1
fi

pid=$1
jstack_cmd=""

if [[ $JAVA_HOME != "" ]]; then
  jstack_cmd="$JAVA_HOME/bin/jstack"
else
  r=`which jstack 2>/dev/null`
  if [[ $r != "" ]]; then
    jstack_cmd=$r
  else
    echo "can not find jstack"
    exit -2
  fi
fi

#line=`top -H  -o %CPU -b -n 1  -p $pid | sed '1,/^$/d' | grep -v $pid | awk 'NR==2'`

line=`top -H -b -n 1  -p $pid | sed '1,/^$/d' | sed '1d;/^$/d' | grep -v $pid | sort -nrk9 | head -1`
echo "$line" | awk '{print "tid: "$1," cpu: %"$9}'
tid_0x=`printf "%0x" $(echo "$line" | awk '{print $1}')`
$jstack_cmd $pid | grep $tid_0x -A20 | sed -n '1,/^$/p'