Linux/AM5728: OCMC RAM performance

Snehal Patel58

Intellectual 830 points

Part Number: AM5728

Tool/software: Linux

Hi Everyone,

I am using shared memory between A15 and DSP.

I am profiling memcpy,

for OCMC access(memcpy) at a15 taking 37.255 microseconds for 64 KB of data,

while for DDR it's taking 18.382 microseconds for 64 KB of data,

Why OCMC access time is more than DDR?

Is both RAM operating frequency make the difference? (attached reference doc for operation freq. )

Note: I am using cmem module to access this RAM and in both case it is cached.

Regards,

Snehal

over 6 years ago

0 Bin Liu over 6 years ago

TI__Guru**** 172871 points

Hi Snehal,

The expert in this area is out of office this week. I will try to get someone else to look at it.

0 Rex Chang over 6 years ago in reply to Bin Liu

TI__Guru 50170 points

Hi, Snehal,

Please see the discussion in the post, e2e.ti.com/.../705109

Rex

0 Snehal Patel58 over 6 years ago in reply to Rex Chang

Intellectual 830 points

Thanks, Rex,

I have gone through this post.

OCMC is 2x slower than DDR, is it because of ARM hardware page alignment?

Regards.

Snehal

0 Rex Chang over 6 years ago in reply to Snehal Patel58

TI__Guru 50170 points

Hi, Snehal,

Yes, that's what we think happening behind the scene. OCMC performance can be improved slightly by enabling SMP bit of ARM L2ACTLR register which isn't currently in the release SDK.

Rex

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Linux/AM5728: OCMC RAM performance