junxin zhu

'http-nio-BlockPoller' taken more than 90% cpu

I found a problem that when i start my application,after a while,it will taken more than 90% cpu.And in my thread tracking(I use jstack to find threads information),i found a thread that named 'http-nio-BlockPoller',it taken 90% cpu,and in the thread call,i found it locked for a long time,and it shows the problem begins with 'org.apache.tomcat.util.net.NioBlockingSelector$BlockPoller.run(NioBlockingSelector.java:313)'.Then i checked my codes,but i can not find any problems of my code,so it maybe tomcat's problem?Who can teach me how to fixed this problem?Thank you very much!

Report URL - https://fastthread.io/my-thread-report.jsp?p=c2hhcmVkLzIwMjIvMDEvMTgvLS10aHJlYWRzcy56aXAtLTYtMjktMzM=

http-nio-blockpoller
jstack
tomcatsproblem
tomcatbugs
tomcaterrors

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junxin zhu

The report is the newest thread tracking,i restart the application, no problem found now,but i don't know when the problem will happen

Mahesh

Hi Junxin,

Do you have an old thread dump report or a stacktrace of thread "http-nio-BlockPoller"?

junxin zhu

yes,i saved it

junxin zhu

https://fastthread.io/my-thread-report.jsp?p=c2hhcmVkLzIwMjIvMDEvMTgvLS10aHJlYWRzLnppcC0tNi01Ni0xOQ==&;

sainath

Hi Junxin,

This report also looks like the same one you attached in the question. Can you please upload the thread dump which contains "http-nio-BlockPoller" consuming 90% CPU.

junxin zhu

"http-nio-57253-BlockPoller" #16 daemon prio=5 os_prio=0 tid=0x00007fbdf527e800 nid=0x38394 runnable [0x00007fbdcc7ea000]
java.lang.Thread.State: RUNNABLE
at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
- locked <0x00000007011afc68> (a sun.nio.ch.Util$3)
- locked <0x00000007011afc58> (a java.util.Collections$UnmodifiableSet)
- locked <0x00000007011afb30> (a sun.nio.ch.EPollSelectorImpl)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
at org.apache.tomcat.util.net.NioBlockingSelector$BlockPoller.run(NioBlockingSelector.java:313)

sainath

Hi Junxin,

Are you using log4j in your application for logging?

If so most of your HTTP threads are blocked in log4j.

You probably have a log4j level too low (eg trace)

This leads to :

contention
memory allocations
bad performance

Try to set the log4j level to WARN.

This may not correct all your problems, it may help.

junxin zhu

ok,i will try it, thank you! :)

junxin zhu

i use logback for logging, and use a threadpool to output log

junxin zhu

Thank you,this problem maybe fixed, i use your method, and also change the jdk from 8 to 11,tomcat from 9.0.41 to 9.0.56

junxin zhu

'http-nio-BlockPoller' taken more than 90% cpu