Ways to use the --no_stm option more efficiently

Michael Sch,

Other Parts Discussed in Thread: TMS570LS3137

Hey Guys!

Because we are affected by the EMIF silicon bug in the TMS570LS3137 regarding external RAM, we have enabled the --no_stm option for the complete code base.

The reason why we enabled it for everything is, that it is almost impossible to figure out in advance which functions will get pointers to which areas. Analysis of all the possible memory locations at compile time would be a nightmare. Also, our customers do want to implement mixed-critical applications based on our products. For those, the external RAM is being more excessively used (in the unsafe part).

Now, we know that this might affect the performance. So far we could deal with it, but now we needs to optimize certain parts.

We have already analyzed our performance critical parts and we could figure out that there are is no external memory being used.

Do you know any solution, on how to mark just specific functions to NOT be affected by the --no_stm option?

Further, we can ensure, that the stack is always in the TCM RAM.

Would it also be possible, to configure that the --no_stm option does NOT apply for stack operations (push!) by default?

Thanks in advance.

Regards,
Michael

over 9 years ago

0 Michael Sch, over 9 years ago

Intellectual 800 points

By the way:
When will silicon revision D become available?

0 Sunil Oak over 9 years ago in reply to Michael Sch,

TI__Mastermind 49120 points

Michael,

The "--no_stm" option can be applied to each source file separately. So if you have all functions that write to external memory in separate source files, you can set the "--no_stm" compile option for just these files. I am checking with the compiler team if the implementation is such that it can be applied to individual functions.

The TMS570LS3137 rev D samples are expected to be available around the end of June 2015.

Regards,
Sunil

0 Sunil Oak over 9 years ago in reply to Sunil Oak

TI__Mastermind 49120 points

Michael,

I have verified that the "--no_stm" option works only at a file level.

Regards,
Sunil

0 Michael Sch, over 9 years ago in reply to Sunil Oak

Intellectual 800 points

Sunil,

thanks a lot for the quick response.

As I understood, we should move our performance critical parts (where we verified that no access to the external RAM may occur) into separate source files.
Those will be compiled without the --no_stm option then.

But please forward the following improvement proposals to the compiler development team:

Another option would be very, very convenient that excludes the stack push operations (hopefully no one will think of placing the stack into an external memory)
Function-specific pragmas which allow better control would also be helpful

Regards,
Michael

0 Sunil Oak over 9 years ago in reply to Michael Sch,

TI__Mastermind 49120 points

Michael,

Yes, I will send the improvement proposals to the compiler team.

Regards,
Sunil

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Ways to use the --no_stm option more efficiently