Best way to do memory testing?

Hi,

My name is Shaun VanWeelden and I am working on a project to look at script performance. A large part of what I do is gather code to evaluate and see what errors are thrown, etc. I also try and do performance testing (using tic toc) and memory usage. We currently do memory testing the following way:

           %Get initial memory being used
           [user, sys] = memory ;
           mStart = user.MemUsedMATLAB ;

           %Get initial start time
           tic
               %Run the actual script, the 'evalc" suppresses all output,
               %do "eval" without the c to see program output
               evalc(the script); 

           %Figure out how long script took to run    
           time=toc;

           %Calculate total memory used and add it to the cell array
           [user, sys] = memory ;
           mtotal = user.MemUsedMATLAB - mStart;

But this has provided very inconsistent results due to the large number of other things going on inside the testing script. I was wondering if there was a better way to get the individual scripts we are testing’s memory use.

Thank you and let me know if you have any additional questions!

-Shaun VanWeelden

[Shashank Prasanna]

what does a typical "the script" look like?

[Shaun VanWeelden]

Almost anything to be honest, lets just say if I wanted to run every product demo and evaluate it or something like that, it needs to be a pretty flexible program, whats your ideas? Even if it won't work completely with what I am trying to do

Answer 1

[Jan]

Did you read http://undocumentedmatlab.com/blog/profiling-matlab-memory-usage/ already?

A lot of important details of the memory usage cannot be measured by calling memory before and after calling a script or a function. Example:

function out = func1
out = rand(1000, 1000);
for ii = 1:numel(out)
  out(ii) = sqrt(sin(abs(out(ii) - 1)));
end
end

function out = func2
tmp = rand(1000, 1000);
out = sqrt(sin(abs(tmp - 1)));
end

Answer 2

[Image Analyst]

Did you see the "profile" function in the help?

[Shaun VanWeelden]

Very helpful, thank you!

Answer 3

[Shashank Prasanna]

Since we are talking undocumented, do check out feature('memstats') I am not sure how you will use this, but it gives a lot more information than memory does.

[Cedric]

Interesting to compare to structs returned by memory() ..

 >> T = evalc('feature(''memstats'')') ;
 >> str2mat(regexp(T, '(?<=Use:\s*)\d+', 'match'))