rtems size and performance measurement

[Joel Sherrill]

Peter Mueller wrote:
> 
> Hi,
> 
> I want to know how to figure out how may memory (ram) is required for my
> application and rtems itself. Can I trust the figures printed out after the
> built (via size?) or is there a better method (during runtime and/or static)?
> Is there some dynamic memory needed during startup?
> 
> At the moment we have the problem that our system crashs during startup.
> Init is not reached. A smaller application runs without problems. Size
> displays the following figures: text 121k, data 6.3k bss 16.7k. We have 256kb Ram.
> Code and app goes in ram for debugging. On the first look everything should
> work. In the linker script there are 0x20000 for heap and 0x2000 for stack.
> Could be this a problem?

0x20000 heap + 121K text is close to 256K.  That sounds like the problem
to me.

I don't know precisely how your BSP is doing the heap/workspace size but
in this case, hardcoding the heap and stack size is probably bad.  You
might
also want to lower that 0x2000.  Look at see how much is actually used. 
I
would be surprised if it was over 1-2K.  You have reserved 8K.

The gen68360 BSP is a good example of handling RAM allocation based upon
putting the workspace immediately following the .bss, then grabbing 
the rest of physical memory for the C program heap.  Your BSP should 
switch to doing this.  
 
> Futhermore I want to measure some performance data (task switch ....). I
> found some figures on the m68k porting paper for ppc. I want to do this for
> 68332. Is there a recommended method how to do this?

Run the Timing Tests (tmtests) and they report these numbers.  tm26 in
particular
has the context switch times.  tmck should be run first to make sure
your
timer driver is fairly sane (10000 times in a loop takes approximately
10 times
longer than 1000 times, etc).

> Regards,
> Peter
> 
> --
> Sent through GMX FreeMail - http://www.gmx.net

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel at OARcorp.com                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
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