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  1. #1
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    6630 Jerky Games

    Has anyone had any problems with jerky games on the 6630.

    Ive got a game that starts off very jerky then the game seems to smooth out the more you play.

  2. #2
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    Yes - it seems if your game classes have large methods the JIT can take a long (by game standards) time to compile them and this causes the jerky gameplay.

  3. #3
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    6630 JIT Compiler

    How do we know that the 6630 has a JIT compiler, have nokia realeased information about this?

  4. #4
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    I'm pretty sure all Series 60 v2.x devices have the Monty VM.

  5. #5
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    Unfortunately we've not found a solution to the jerkiness - if you find one yourself I would be very grateful if you would be kind enough to share it.

  6. #6
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    If Monty VM has a JIT and the JIT is the cause of the problem then the Nokia 6600 would show the same symptoms as the Nokia 6630, however it does not.

    We have tried a build that does not use midp2 or nokia API device calls and this does not fix the problem.

  7. #7
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    It's seems that jitter occur when code execution meet large "if (expression) {}" block - it is not compiled until expression match requirements - and then it takes some time to compile (load) bytecode and execute that lengthy block. After the code is compiled it is cached - so , the game run smooth ,after all possible game events occured- at least one time . Such jitter reported for almost any S60 v2 devices. Obvious solution is to avoid long "ifs", "switches" , and methods - divide Your code on small parts ,that VM could compile fastly.

  8. #8
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    Anyone know a workaround for this?

    Can JIT be turned off, or can it precompile the entire program (they are not that big, a 1 sec stall on startup is preferable to random pauses)? If so, how would you tell the phone to do this?

    Are there any properties which could be set in the Manifest.MF which the device responds to? unlikely i know...

    Any way of tricking the JIT into compiling the whole thing? maybe inserting dummy braces into the code might throw it off? eg, change this:

    if (something) {
    ... some code...
    ... some more code...
    }

    to:

    if (something) {
    { ... some code... }
    { ... some more code... }
    }

    How many lines (or bytecode length) does the JIT think is "long"? Without knowing this, its hard to analyse where its going to happen, in order to do something about it.

    due to local variables etc, it is difficult to see how an arbitary block can be split out into helper methods, and if those methods are made "final" (to reduce the overhead of calling them), they may be inlined anyway?

    This has severe implications for the end-users impression of our products, everyone comments on it.

  9. #9
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    I have the same problem too. Adding final or static to the function may ot may not help.

  10. #10
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    Re: 6630 Jerky Games

    I have this identical problem. See this thread:
    http://www.j2me.org/yabbse/index.php...28595#msg28595

    I am desperate to find a solution to this. I mean what is the point of JIT? performance enhancing the game.. so why does it need to make the game suck for the first few levels first. My code runs very smooth on ngage - only 6630/6680 display this behaviour, not even 3230.

    Having said that Im willing to admit the complexity is massive, and thereis probably room for optimisation., But like someone posted earlier, this could all be a biiig biig waste of time without knowing what exactly to target. Someone please explain the jit better, and give us a hack to get round it :-)

    If only someone at nokia was reading...

  11. #11
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    Re: 6630 Jerky Games

    We are experiencing the same problem here.

    Does anyone have any new information about this problem?
    Is there a way to turn JIT off?

  12. #12
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    May 2003
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    Re: 6630 Jerky Games

    The workaround is to run through the game(or the parts the require the most computing power) once using autopilot(AI), and disguise it as a loading screen

    My oh my, its year 2005 already and Nokia still come out with these joke phones.

  13. #13
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    Re: 6630 Jerky Games

    Hehehe, yeah i was hoping for some other work around

    This exactly what we were hoping to avoid

    Thx

  14. #14
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    Sep 2005
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    Re: 6630 Jerky Games

    好玩吗? ~~~~~

  15. #15
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    china
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    Re: 6630 Jerky Games

    nice , i will be try

    Denis

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