High CPU in selector polls with HTTP/2 enabled on EAP 7

Solution Verified - Updated

Environment

  • JBoss Enterprise Application Platform (EAP)
    • 7

Issue

  • On EAP 7, we note high CPU in default I/O threads performing selector polls:
"default I/O-24" #142 prio=5 os_prio=0 tid=0x0000000005e7a800 nid=0x1ce7d runnable [0x00007fff4b934000]
   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 <0x00000000899d7720> (a sun.nio.ch.Util$3)
        - locked <0x00000000899d7730> (a java.util.Collections$UnmodifiableSet)
        - locked <0x00000000899d76d8> (a sun.nio.ch.EPollSelectorImpl)
        at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
        at org.xnio.nio.WorkerThread.run(WorkerThread.java:551)

Resolution

This was fixed in EAP 7.2 CP 3. Please, upgrade to the latest version available to have all the fixes applied.

As a workaround, disable HTTP2 on Undertow listener if no HTTP2 traffic is present in the network.

                <http-listener name="default" socket-binding="http" redirect-socket="https" enable-http2="false"/>

If seeing this without HTTP/2, then consider High CPU in selector polls on EAP 7

Root Cause

Check the below Jira related to the issue:

SBR
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