CPU surge problem location

CPU Soaring problem positioning

happen CPU The situation of soaring can be jstack Command positioning problem ,jstack + pid Look for deadlocks .
Test code

package com.aword.demo.jvm;
public class CPUDemo {
    public int compute() {
        int a = 1;
        int b = 2;
        int c = (a + b) * 10;
        return c;
    }
    public static void main(String[] args) {
        CPUDemo cpuDemo = new CPUDemo();
        while (true) {
            cpuDemo.compute();
        }
    }
}

Compile the class to CPUDemo.class Put the file in the local virtual machine
Carry out orders java com.aword.demo.jvm.CPUDemo
Start to check the progress

top

Check the memory of the process

top -p pid

Press H , Get the details of each thread .

find CPU The highest thread occupied tid, To 16 Base number .

printf %x tid

perform jstack Get the thread stack information after the line 10 That's ok , You can see from the stack what causes cpu Skyrocketing call method .

jstack pid | grep -A 10  Hexadecimal tid

Check the corresponding stack information to find out the code that may have problems

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