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C66x FFT Benchmarks / Algorithm latency

Jim Schwendeman1
Prodigy 90 points

Howdy Forum,

I'd like to do some cycle estimates on a specific algorithm before committing to hardware.  My plan was to determine cycle estimates based off of available benchmarks, and then continue with simulation if the preliminary numbers looked appropriate.  The main operations I'll need to implement will be FFT, IFFT, and element-wise multiplication.

I'm looking for C66x Benchmarks, similar to what TI has provided for the C64x here: http://www.ti.com/lsds/ti/dsp/c6000_dsp/c64x/benchmarks.page

Any thoughts?

  • 0
    TI__Guru** 115950 points

    Hi Jim,

    If you download the DSPLIB 3.1.1.1.for C66x , you will find the performance benchmarks in the Test reports in the doc folder. This can also be accessed from the link below:

    http://software-dl.ti.com/sdoemb/sdoemb_public_sw/dsplib/latest/exports/DSPLib_c66xTest_Report.html

    Regards,

    Rahul

  • 0 in reply to Rahul Prabhu
    Prodigy 90 points

    Rahul,

    To continue with this line of questioning, I'm trying to verify this result from the test reports using the existing FFT_Example_66_LE_COFF:

    DSP_fft16x16_66_LE_COFF_c66-LE-COFF 1 (TCI6608-DevFuncSim-LE) ccs_base Passed " 461 (N=128) 752 (N=256)" " 1472 bytes"

    When I run, however, I get the following results:

    [TMS320C66x_0]
    overhead = 2
    start, stop, time fft16x16 = 337239, 337962, 721
    start, stop, time fft16x32 = 348360, 349767, 1405
    start, stop, time fft32x32 = 360340, 361739, 1397

    I should note that I changed N from 256 to 128 in the example project, so my expected result should be the 461 cycles.

    My target config is selected as C6678 Device Cycle Approximate Simulator, little endian.  However, when I go to Build Properties, the variant is "Custom C6000 Device".

    1. How should I change this to get the correct cycle estimates found in the benchmarks test report?
    2. How can I change the variant without blowing away all the "includes" and other settings relative to the project?
    Thanks!
    Jim