Java CPU性能分析工具代码实例

这篇文章主要介绍了Java CPU性能分析工具代码实例,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

背景

有处理过生产问题的同学基本都能遇到系统忽然缓慢，CPU突然飙升，甚至整个应用请求不可用。当出现这种情况下，在不影响数据准确性的前提下，我们应该尽快导出jstack和内存信息，然后重启系统，尽快回复系统的可用性，避免用户体验过差。本文针对CPU飙升问题，提供该问题的排查思路，从而能够快速定位到某线程甚至某快代码导致CPU飙升，从而提供处理该问题的思路。

排查过程

通过以上步骤可以查找出导致cpu飙升的相关代码位置，然后对代码进行code review即可。

工具封装

以上步骤已经封装为脚本文件,通过以下脚本文件只需要指定进程ID即pid即可导出默认前5条导致CPU率过高的堆栈信息。

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./java-thread-top.sh -p pid

#!/bin/bash# @Function# Find out the highest cpu consumed threads of java processes, and print the stack of these threads.# @github https://github.com/cjunn/script_tool/# @author cjunn# @date Sun Jan 12 2020 21:08:58 GMT+0800#pid='';count=5;function usage(){  readonly PROG="`basename $0`"  cat <<EOFUsage: ${PROG} [OPTION]Find out the highest cpu consumed threads of java processes,and print the stack of these threads.Example: ${PROG} -p <pid> -c 5   # show top 5 busy java threads infoOutput control: -p, --pid <java pid>   find out the highest cpu consumed threads from              the specified java process.              default from all java process. -c, --count <num>     set the thread count to show, default is 5.Miscellaneous: -h, --help        display this help and exit.EOF}#1.Collect script parameters#2.Check whether PID existsif [ $# -gt 0 ];then  while true; do    case "$1" in    -c|--count)      count="$2"      shift 2      ;;    -p|--pid)      p      shift 2      ;;    -h|--help)      usage      exit 0;      ;;    --)      shift      break      ;;    *)      shift      if [ -z "$1" ] ; then        break      fi      ;;    esac  donefiif [ ! -n "$pid" ] ;then  echo "error: -p is empty"  exit 1;fifunction worker(){  #1.Query all threads according to PID.  #2.Delete header and first line information.  #3.According to the second column of CPU to sort, reverse display.  #4.Delete the count + 1 to last column based on the count value.  #5.Get CPU utilization, TID value, thread used time, and assign them to CPU, TID, time respectively.  #6.Perform hex conversion on TID.  #7.Use JDK to monitor all threads of jstack output PID.  #8.Use awk to regularly query the thread information of tid_hex required.  #9.Display the stack information of count before thread busy.  local whilec=0;  ps -mp $pid -o THREAD,tid,time | sed '1,2d' | sort -k 2 -n -r |sed $[$count+1]',$d' | awk '{print $2,$8,$9}' | while read cpu tid time  do      tid_hex=$(printf "%x" $tid);      echo "====================== tid:${tid} tid_hex:${tid_hex} cpu:${cpu} time:${time} ======================";      jstack $pid | awk 'BEGIN {RS = "/n/n+";ORS = "/n/n"} /'${tid_hex}'/ {print $0}'      echo "";      whilec=$[$whilec+1];  done  if [ $whilec -eq 0 ] ; then    echo "error : thread not found, make sure pid exists.";  fi}worker