TMS320C6678: C66x Simulator benchmarking issue

ilan ovadia

Part Number: TMS320C6678

Hi,

I run the example project "DSPF_sp_fftSPxSP_66_LE_ELF" of the "dsplib_c66x_3_4_0_0" on the "C6778 Device Cycle Approximate Simulator Little Endian".

The code and the data were placed at the L2 SRAM.

When I set the L2 SRAM address to the aliased address 0x800000 the performance cycles were about 8000.

But when I set the L2 SRAM address to the global address 0x10800000 the results were about 14000 cycles.

Why the results are not the same and what shlould I do to improve the results with global address ?

Thanks,

Ilan

over 7 years ago

0 Cvetolin Shulev-XID over 7 years ago

TI__Guru 65405 points

The team is notified. They will post their feedback directly here.

BR
Tsvetolin Shulev

0 Yordan Kovachev over 7 years ago

TI__Guru**** 161600 points

Hi,

I've notified the RTOS team. They will post their feedback directly here.

Best Regards,
Yordan

0 Rahul Prabhu over 7 years ago

TI__Guru** 116170 points

Ilan,

C66x simulators are no longer supported by TI so we are not supporting an simulator related issues. I can`t provide more guidance beyond the thoughts that are mentioned below:

My guess would be when you use internal addressing the DSP can directly access L2 but when you use global address the call goes to the interconnect and gets redirected to internal memory so the interconnect latency is added to the overall cycle count. 6000 cycles on a 1 Ghz DSP is 6 microseconds which seems a little high. Have you tried this on actual silicon?

Regards,
Rahul

0 ilan ovadia over 7 years ago in reply to Rahul Prabhu

Prodigy 220 points

Hi Rahul,

Thank you for the reply.

I already discovered this problem on the EVM board with my project.

So I tried the TI example on the simulator, and it didn't get better.

Thanks,
Ilan

0 ilan ovadia over 7 years ago in reply to ilan ovadia

Prodigy 220 points

Hi Rahul,

I run the TI example on the EVM board as you suggested and there were no difference between the alias address and the global address performance.

Thanks,
Ilan

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TMS320C6678: C66x Simulator benchmarking issue