Slow DSP67x.lib

William Schaecher

I am using the DSP67x.lib with the OMAP L137. I am comparing the single precision dot-product (multiply-add) to the C language equivalent and there is not much difference. For example, a 1000 point multiply-add should take about 1000/2 * 10 ns = 5 us and it is taking about 120 us on a 300 MHz OMAP 674x DSP. It is as if the instruction cache is not enabled. When I execute the GEL command to enable the instruction cache, I get

Enable_Instruction_Cache() cannot be evaluated.

identifier not found: CPSR

at CPSR=0x400000d3 [dskda830_dsp.gel:637]

at Enable_Instruction_Cache()

Any ideas?

over 10 years ago

0 Titusrathinaraj Stalin over 10 years ago

TI__Guru** 116100 points

Hi William,
I think, you have called "Enable_Instruction_Cache()' function manually through scripts option.
ARM core only had support for I-cache and D-cache whereas DSP doesn't support.

0 William Schaecher over 10 years ago in reply to Titusrathinaraj Stalin

Prodigy 30 points

I am getting slower that expected performance from the c674x-DSPLIB. I expect a multiply-add (dot-product) to take about 10 ns @ 300MHz, yet it is taking 120 ns. Do I have a setup problem?

0 Titusrathinaraj Stalin over 10 years ago in reply to William Schaecher

TI__Guru** 116100 points

If you want to increase the performance then you can increase the processor speed from 300MHz to 456MHz then test it again.
OMAPL137 can support 456MHz operating frequency.

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Slow DSP67x.lib