ADDITIONAL SYSTEM INFORMATION :
Red Hat Enterprise Linux 7.9
openjdk version "1.8.0_312"
OpenJDK Runtime Environment (build 1.8.0_312-b07)
OpenJDK 64-Bit Server VM (build 25.312-b07, mixed mode)


A DESCRIPTION OF THE PROBLEM :
We're using WSO2 API Manager, running currently on OpenJDK 8u312. We updated a few days ago from 8u302 to 312.

After that update, our app is started to produce 100% CPU usage after receiving one single request. After restarting the app, the CPU usage normalizes, but then with another request, it goes up again to 100%.

Based on the thread dump, those two threads are using the most CPU resources:

"HTTPS-Listener I/O dispatcher-2" #268 prio=5 os_prio=0 tid=0x00007f169c140000 nid=0x2e5d runnable [0x00007f1652a20000]
   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 <0x00000000cb2c03e0> (a sun.nio.ch.Util$3)
- locked <0x00000000cb2c03d0> (a java.util.Collections$UnmodifiableSet)
- locked <0x00000000cb2c0298> (a sun.nio.ch.EPollSelectorImpl)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:256)
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:105)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:586)
at java.lang.Thread.run(Thread.java:748)

"HTTPS-Listener I/O dispatcher-1" #267 prio=5 os_prio=0 tid=0x00007f169c13e000 nid=0x2e5c runnable [0x00007f1652b21000]
   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 <0x00000000cb2c0ba8> (a sun.nio.ch.Util$3)
- locked <0x00000000cb2c0b98> (a java.util.Collections$UnmodifiableSet)
- locked <0x00000000cb2c0a60> (a sun.nio.ch.EPollSelectorImpl)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:256)
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:105)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:586)
at java.lang.Thread.run(Thread.java:748)


REGRESSION : Last worked in version 8


FREQUENCY : always