I'd like to have a tool that shows how much time was spent in each
function when the program was run.

There is some tool like this, I know. I just can't remember the
name. Actually I believe that there are several tools like this. Can
anyone recommend something? Was there some GNU tool for this purpose?

reg,
Juha

--
+  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +
Juha Mynttinen
J?mer?ntaival 11 G 158        
02150 Espoo                
040 - 531 6872              

clock_t start,duration;

start=clock();
/* stuff */
duration=clock()-start;

You are probably after a "profiler".

Bill, took 36 seconds.

use "quantify" tool.

If you have access to a VMS system with "DECSET" installed you can use
PCA.  It's very good for this sort of thing and can analyze your program
several different ways, under different run conditions, and so forth.  
Here's part of the HELP file:

     The DIGITAL Performance and Coverage Analyzer (PCA) is a software
     development tool that helps you analyze the run-time behavior
     of application programs. The DIGITAL Performance and Coverage
     Analyzer can pinpoint execution bottlenecks and other performance
     problems in user programs. Using this information, you can modify
     your programs to run faster. This tool also measures which parts
     of your program are or are not executed by a given set of test
     data so that you can devise tests that exercise all parts of your
     program.

A couple of weeks ago PCA helped me find a performance problem having to do
with arrays vs. cache sizes.

The code (fortran) was:

  do i=1,N
    a(i)=0
    b(i)=0
  end do

The size of the arrays a and b had been increased and as a consequence they
no longer both fit into cache at the same time. This caused a huge
performance hit which PCA localized to this section of code.  Reordering
the code to:

  do i=1,N
    a(i)=0
  end do
  do i=1,N
    b(i)=0
  end do

fixed it.

Regards,

David Mathog

Manager, sequence analysis facility, biology division, Caltech