Playframework unusual CPU load

Recently we started using PlayFramework and seeing some unusual activity in CPU load.

Machine details and other configurations:

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  • 32G Machine
    12  Cores
    PlayFramework 2.2.0
    java -Xms1024m -Xmx1024m -XX:MaxPermSize=256m -XX:ReservedCodeCacheSize=128m
    java applications are running within a docker container(Docker version 0.8.0).
    

    There are 6 play server running behind nginx

    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
    31752 root      20   0 7876m 1.2g  14m S  716  3.8 150:55.28 java
    26282 root      20   0 7862m 1.2g  14m S   48  3.8 310:51.65 java
    56449 root      20   0 7789m 389m  13m S    2  1.2   0:33.10 java
    40006 root      20   0 7863m 1.2g  14m S    2  3.8  17:56.41 java
    42896 root      20   0 7830m 1.2g  14m S    1  3.8  15:10.30 java
    52119 root      20   0 7792m 1.2g  14m S    1  3.7   8:48.38 java
    

    The request rate is at max 100Req/s.

    Has anyone faced this similar issues before?
    Please let me know.

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  • 2 Solutions collect form web for “Playframework unusual CPU load”

    I am experiencing a similar issue. However, I am only having trouble with the dev setup on my machine:

    • play! application started via play run
    • within a docker container
    • that is running inside a VM

    -> 100% CPU load inside the VM

    Problem does not exist in our live environment, where the application is run pre-packaged via the start script. We also have it running in a docker container there (which in turn runs in an EC2 VM).

    So it seems like in my case play run makes a difference – are you using play run to start your app inside the docker container?

    EDIT: Also, there seems to be a bug in Netty related to epoll selectors:
    http://www.electrotank.com/forums/showthread.php?12927-Well-Known-JDK-bug-in-Netty
    https://code.google.com/p/spymemcached/issues/detail?id=279

    The second link describes a workaround that involves setting the -XX:CMSInitiatingOccupancyFraction JVM parameter to 80 or something.

    In my case, this did not help however…

    You might consider profiling your java process e.g. using

    sudo strace -cf -p <pid>
    

    and see if anything suspicious shows up.

    How are you running the play app? I have experienced a similar high load when running with play ~run, because it watches files for changes constantly.

    Docker will be the best open platform for developers and sysadmins to build, ship, and run distributed applications.