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difference between simulator and emulator numbers in ARM926EJS

Discussion in 'Embedded' started by sekar, May 10, 2007.

  1. sekar

    sekar Guest

    Hi I am new to ARM. I have a aac decoder which i run in arm. It is
    working fine and it is perfectly matching. But the performance numbers
    between simulator and emulator differs widely.

    In Simulator it is around 20Mcycles. But when i run the same in
    emulator it takes around 10 to 20 times higher with catch enable.

    As a test I tried a single load from same location for 100 times and
    on average it takes around 10 cycles with catch enable and around 80
    to 90 cycles with catch disabled.

    If any one has come across such problems pls suggest me a solution to
    this.

    thanks in advance.
    With Regards,
    Dhanasekaran
     
    sekar, May 10, 2007
    #1
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  2. sekar

    Hans Odeberg Guest

    Have you configured the memory wait states in the simulator to match
    those of the emulator? If the simulator fetches data from external
    memory in a single cycle, it is not very surprising that it is faster
    than the emulator - an aac decoder is large enough to be hitting the
    external memory a bit.
     
    Hans Odeberg, May 10, 2007
    #2
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  3. sekar

    sekar Guest


    Hi pls note I have enabled cache.
    also I have tested using single instruction repeated about 100 times.
    Since it is catched it should have only one cycle (approx) atleast
    for this portion of code.
    But for me it takes around 10 cycle on average
     
    sekar, May 10, 2007
    #3
  4. sekar

    Hans Odeberg Guest

    OK, now you have me stumped.

    Can you provide any further details that might help? The exact
    assembly instruction you are executing to fetch the data, for example.
    Can you get any trace printouts from the emulator?

    /Hans
     
    Hans Odeberg, May 11, 2007
    #4
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