weblogic高cpu分析

最新推荐文章于 2021-02-27 14:29:43 发布

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最新推荐文章于 2021-02-27 14:29:43 发布

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分类专栏： weblogic 文章标签： weblogic 线程 native

本文链接：https://blog.youkuaiyun.com/glenn_g/article/details/12168819

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本文介绍了一种排查Java Web应用程序中CPU占用过高的方法，包括如何定位问题线程及分析线程堆栈，最终找到导致高CPU占用的代码位置。

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程序代码

Web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5"

xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

<description>This is the description of my J2EE component</description>

<display-name>This is the display name of my J2EE component</display-name>

<servlet-name>HeapOOM</servlet-name>

<servlet-class>com.mem.HeapOOM</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>HeapOOM</servlet-name>

<url-pattern>/servlet/HeapOOM</url-pattern>

</servlet-mapping>

<welcome-file-list>

<welcome-file>/</welcome-file>

</welcome-file-list>

</web-app>

DeadLoop.java

package com.cpu;

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.IOException;

import javax.servlet.http.HttpServlet;

public class DeadLoop extends HttpServlet {

public void init(ServletConfig config) throws ServletException

{

super.init(config);

}

public void service(HttpServletRequest request,HttpServletResponse response) throws IOException

{

try{

while(true){

Math.exp(Math.PI);

}

catch(Exception e){

while(true){

Math.exp(Math.PI);

}

查看cpu状态为剩余百分比为25.5%，使用kill -3 pid命令收集线程堆栈相关信息。

[weblogic@rh5 ~]$top

top - 04:02:22 up 1 day, 5:00, 5 users, load average: 1.83, 1.28, 0.97

Tasks: 142 total, 3 running, 139 sleeping, 0 stopped, 0 zombie

Cpu(s): 59.2%us, 14.7%sy, 0.0%ni, 25.5%id, 0.3%wa, 0.0%hi, 0.4%si, 0.0%st

Mem: 2075424k total, 1785188k used, 290236k free, 183056k buffers

Swap: 5144568k total, 0k used, 5144568k free, 795848k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

9059 weblogic 18 0 786m 253m 19m S 34.1 12.5 28:30.90 java

9761 root 25 0 2552 1044 604 R 2.1 0.1 0:00.34 find

637 root 11 -5 0 0 0 S 0.1 0.0 0:02.45 kjournald

2770 root 15 0 1728 576 480 S 0.1 0.0 0:00.09 syslogd

7908 weblogic 20 0 811m 452m 25m S 0.1 22.3 2:27.79 java

9295 weblogic 15 0 2336 1052 800 R 0.1 0.1 0:00.12 top

9377 root 16 0 2412 956 836 S 0.1 0.0 0:00.01 run-parts

9743 root 18 0 2412 1000 836 S 0.1 0.0 0:00.01 makewhatis

1 root 25 0 2072 616 532 S 0.0 0.0 0:01.05 init

2 root RT -5 0 0 0 S 0.0 0.0 0:00.27 migration/0

3 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0

4 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/0

5 root RT -5 0 0 0 S 0.0 0.0 0:00.26 migration/1

6 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/1

7 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/1

使用命令top -H -p pid 收集占用进程中使用cpu较大的线程信息，得到占用cpu较大的的线程号9090

将得到的线程号转换为16进制得到0x2382

[weblogic@rh5 ~]$ top -H -p 9059

top - 04:03:21 up 1 day, 5:01, 5 users, load average: 2.09, 1.37, 1.00

Tasks: 39 total, 2 running, 37 sleeping, 0 stopped, 0 zombie

Cpu(s): 0.7%us, 0.1%sy, 0.0%ni, 99.2%id, 0.1%wa, 0.0%hi, 0.0%si, 0.0%st

Mem: 2075424k total, 1793520k used, 281904k free, 183104k buffers

Swap: 5144568k total, 0k used, 5144568k free, 804436k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

9090 weblogic 25 0 786m 253m 19m R 12.2 12.5 26:39.52 java

9075 weblogic 25 0 786m 253m 19m R 11.5 12.5 1:57.86 java

9059 weblogic 18 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9060 weblogic 16 0 786m 253m 19m S 0.0 12.5 0:02.57 java

9061 weblogic 18 0 786m 253m 19m S 0.0 12.5 0:00.06 java

9062 weblogic 16 0 786m 253m 19m S 0.0 12.5 0:00.06 java

9063 weblogic 17 0 786m 253m 19m S 0.0 12.5 0:00.06 java

9064 weblogic 17 0 786m 253m 19m S 0.0 12.5 0:00.04 java

9065 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.61 java

9066 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9067 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9068 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9069 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:02.71 java

9070 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:02.69 java

9071 weblogic 25 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9072 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.01 java

9073 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9074 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.01 java

9076 weblogic 18 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9077 weblogic 16 0 786m 253m 19m S 0.0 12.5 0:00.03 java

9078 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.17 java

9079 weblogic 24 0 786m 253m 19m S 0.0 12.5 0:00.06 java

9080 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.01 java

9081 weblogic 24 0 786m 253m 19m S 0.0 12.5 0:00.01 java

9082 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.01 java

9083 weblogic 19 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9085 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9086 weblogic 18 0 786m 253m 19m S 0.0 12.5 0:00.05 java

9087 weblogic 15 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9088 weblogic 17 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9089 weblogic 18 0 786m 253m 19m S 0.0 12.5 0:00.00 java

9092 weblogic 18 0 786m 253m 19m S 0.0 12.5 0:00.01 java

9093 weblogic 18 0 786m 253m 19m S 0.0 12.5 0:00.01 java

通过得到的线程号在收集的线程堆栈中找到对应的“0x2382”，此时我们可以看到在nid=0x2382 线程出现“stuck” 查看报错信息可以看到“at com.cpu.DeadLoop.service(DeadLoop.java:19)”

通过报错信息对代码进行修改

"[STUCK] ExecuteThread: '2' for queue: 'weblogic.kernel.Default (self-tuning)'" daemon prio=10 tid=0x890e0400 nid=0x2382 runnable [0x886fe000]

java.lang.Thread.State: RUNNABLE

at java.lang.StrictMath.exp(Native Method)

at java.lang.Math.exp(Math.java:237)

at com.cpu.DeadLoop.service(DeadLoop.java:19)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)

at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)

at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:301)

at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:184)

at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3732)

at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3696)

at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)

at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)

at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2273)

at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2179)

at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1490)

at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)

at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)