The execution time of software

Thank you very much.

In my system, I have only one output was connected to GPIO for get the signal (the execution time - signal = 1 the function are processing, signal =0 the function aren't processing). From that information I found the execution time of my process.

the procedure of my system below:

Firstly, Nios II sends zero to FPGA ~~~~> Secondly, Nios II processes the function (which I need to know the execution time) ~~~~> Thirdly, Nios II sends one to FPGA.

The signal (0 and 1) was sent from Nios to FPGA, I can measure from the GPIO of FPGA board.

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The execution times are reasonably fixed (and determinable) provided that:

1) there is no contention for Avalon slaves

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Can you tell me more information about this?

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2) there are no delays waiting for anything external (eg JTAD UART)

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In FPGA board I have only one SOPC and one pin connect to 1 GPIO

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3) the cache transfers are the same

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What is the cache transfers. Where can I check it?

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4) the branch predictor behaves the same way.

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What is the branch predictor behaves?

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To get trully determinable execution times you need to use tightly coupled memory for code and (most) data, and to disable the dynamic branch prediction.

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I didn't have any code In FPGA board accept SOPC and one output.