difference between simulator and emulator numbers in ARM926EJS

May 10, 2007 3 Replies
S

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



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H

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.

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S

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

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H

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

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