龙空技术网

jstack排查cpu高问题四步走

IT技术圈 1668

前言:

眼前朋友们对“jstack定位g问题”可能比较注重,同学们都需要分析一些“jstack定位g问题”的相关文章。那么小编同时在网上搜集了一些关于“jstack定位g问题””的相关文章,希望小伙伴们能喜欢,各位老铁们快快来了解一下吧!

步骤一:查看cpu占用高进程

执行top命令后,按shift+p 按cpu使用量排序

topMem:  16333644k total,  9472968k used,  6860676k free,   165616k buffersSwap:        0k total,        0k used,        0k free,  6665292k cached  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND     17850 root      20   0 7588m 112m  11m S 100.7  0.7  47:53.80 java        1552 root      20   0  121m  13m 8524 S  0.7  0.1  14:37.75 AliYunDun    3581 root      20   0 9750m 2.0g  13m S  0.7 12.9 298:30.20 java            1 root      20   0 19360 1612 1308 S  0.0  0.0   0:00.81 init            2 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kthreadd        3 root      RT   0     0    0    0 S  0.0  0.0   0:00.14 migration/0
步骤二:查看cpu占用高线程

通过第一步得到了进程号

通过top -Hp 进程号,查看具体的线程情况

top -H -p 17850top - 17:43:15 up 5 days,  7:31,  1 user,  load average: 0.99, 0.97, 0.91Tasks:  32 total,   1 running,  31 sleeping,   0 stopped,   0 zombieCpu(s):  3.7%us,  8.9%sy,  0.0%ni, 87.4%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%stMem:  16333644k total,  9592504k used,  6741140k free,   165700k buffersSwap:        0k total,        0k used,        0k free,  6781620k cached  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND17880 root      20   0 7588m 112m  11m R 99.9  0.7  50:47.43 java17856 root      20   0 7588m 112m  11m S  0.3  0.7   0:02.08 java17850 root      20   0 7588m 112m  11m S  0.0  0.7   0:00.00 java17851 root      20   0 7588m 112m  11m S  0.0  0.7   0:00.23 java17852 root      20   0 7588m 112m  11m S  0.0  0.7   0:02.09 java17853 root      20   0 7588m 112m  11m S  0.0  0.7   0:02.12 java17854 root      20   0 7588m 112m  11m S  0.0  0.7   0:02.07 java
步骤三:转换线程ID

通过第二步得到了线程17880有问题,转换成16进制,以便后续使用。

printf "%x\n" 17880          45d8
步骤四:定位cpu占用线程

在jstack打印的堆栈信息中查询线程相关信息

jstack 17850|grep 45d8 -A 30"pool-1-thread-11" #20 prio=5 os_prio=0 tid=0x00007fc860352800 nid=0x45d8 runnable [0x00007fc8417d2000]   java.lang.Thread.State: RUNNABLE        at java.io.FileOutputStream.writeBytes(Native Method)        at java.io.FileOutputStream.write(FileOutputStream.java:326)        at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)        at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)        - locked <0x00000006c6c2e708> (a java.io.BufferedOutputStream)        at java.io.PrintStream.write(PrintStream.java:482)        - locked <0x00000006c6c10178> (a java.io.PrintStream)        at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221)        at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:291)        at sun.nio.cs.StreamEncoder.flushBuffer(StreamEncoder.java:104)        - locked <0x00000006c6c26620> (a java.io.OutputStreamWriter)        at java.io.OutputStreamWriter.flushBuffer(OutputStreamWriter.java:185)        at java.io.PrintStream.write(PrintStream.java:527)        - eliminated <0x00000006c6c10178> (a java.io.PrintStream)        at java.io.PrintStream.print(PrintStream.java:597)        at java.io.PrintStream.println(PrintStream.java:736)        - locked <0x00000006c6c10178> (a java.io.PrintStream)        at com.demo.guava.HardTask.call(HardTask.java:18)        at com.demo.guava.HardTask.call(HardTask.java:9)        at java.util.concurrent.FutureTask.run(FutureTask.java:266)        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)        at java.lang.Thread.run(Thread.java:745)"pool-1-thread-10" #19 prio=5 os_prio=0 tid=0x00007fc860345000 nid=0x45d7 waiting on condition [0x00007fc8418d3000]   java.lang.Thread.State: WAITING (parking)        at sun.misc.Unsafe.park(Native Method)        - parking to wait for  <0x00000006c6c14178> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)

标签: #jstack定位g问题