2 Replies Latest reply: Jan 17, 2007 8:54 AM by 807557 RSS

    Migrating apps to realtime

    807557
      Hello,

      wondering if you've come across any examples whereby JEE applications have been migrated to a realtime vm ? Curious as to effort involved in moving medium sized applictions (100ks lines of code) over - primary motivations are the gc pauses. Does this fundamentally require an app server targeted for a realtime vm ?

      thanks
      d
        • 1. Re: Migrating apps to realtime
          807557
          This would require a Herculean effort. For one thing, you would have to rewrite your application to use scoped memory: a very difficult task. I would look elsewhere for your GC pause problem.
          • 2. Re: Migrating apps to realtime
            807557
            David,

            We ported the GlassFish Application Server to the Java RTS product implementation of the RTSJ in 5 hours including a new feature to open a real-time http connection.

            First, not all of every ported application needs real-time support thus 95% or more just runs as is (since RTSJ is fully, completely, Java). Like in the GlassFish example we changed no code and it ran fine on the real-time JVM. Then we replicated the thread pool creation code and changed it to use instances of javax.realtime.RealtimeThread.

            Converting large applications to completely RTSJ can be very simple, just a syntax change from java.lang.Thread to javax.realtime.RealtimeThread is all that is needed to get a lot of the features of the RTSJ. E.g., in Java RTSJ 2.0 (now in beta) instances of RealtimeThread can execute with a maximum of ONLY 200 microseconds of pause times from the real-time GC.

            Using ScopedMemory and NoHeapRealtimeThreads is only necessary for those bits of logic wich require maximum latencies in the few tens of microseconds (such as low level command loops for high speed physical devices).

            Cheers, Greg
            Hello,

            wondering if you've come across any examples
            whereby JEE applications have been migrated to a
            realtime vm ? Curious as to effort involved in
            moving medium sized applictions (100ks lines of
            code) over - primary motivations are the gc pauses.
            Does this fundamentally require an app server
            targeted for a realtime vm ?

            thanks
            d