Java CPU性能分析工具代码实例

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top命令查看cpu飙升的java进程pid

通过ps -mp [pid] -o THREAD,tid,time查看该进程下所拥有的线程及各个线程占用cpu的使用率，并且记录CPU使用率过高的线程ID号

将线程ID号转换为16进程的数值记为tid_hex

使用jdk自带jstack监控命令

使用命令jstack [pid] | grep tid_hex -A100命令输出该线程的堆栈信息

根据堆栈信息分析代码。

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 <

Usage: ${PROG} [OPTION]

Find out the highest cpu consumed threads of java processes,

and print the stack of these threads.

Example:

${PROG} -p -c 5 # show top 5 busy java threads info

Output control:

-p, --pid find out the highest cpu consumed threads from

the specified java process.

default from all java process.

-c, --count 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 exists

if [ $# -gt 0 ];

then

while true; do

case "$1" in

-c|--count)

count="$2"

shift 2

;;

-p|--pid)

pid="$2"

shift 2

;;

-h|--help)

usage

exit 0;

;;

--)

shift

break

;;

*)

shift

if [ -z "$1" ] ; then

break

fi

;;

esac

done

fi

if [ ! -n "$pid" ] ;then

echo "error: -p is empty"

exit 1;

fi

function 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

Usage: ${PROG} [OPTION]

Find out the highest cpu consumed threads of java processes,

and print the stack of these threads.

Example:

${PROG} -p -c 5 # show top 5 busy java threads info

Output control:

-p, --pid find out the highest cpu consumed threads from

the specified java process.

default from all java process.

-c, --count 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 exists

if [ $# -gt 0 ];

then

while true; do

case "$1" in

-c|--count)

count="$2"

shift 2

;;

-p|--pid)

pid="$2"

shift 2

;;

-h|--help)

usage

exit 0;

;;

--)

shift

break

;;

*)

shift

if [ -z "$1" ] ; then

break

fi

;;

esac

done

fi

if [ ! -n "$pid" ] ;then

echo "error: -p is empty"

exit 1;

fi

function 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

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