This tests measures performance degradation when running parallel
compute-intensive threads on a shared memory machine (pthreads).

Performance degradation is measured for integer addition, multiplication,
division, and floating point addition, multiplication, and for a mix of integer
and floating point operations. No memory is accessed during the computation.

To run this test:
1.) Adjust environment variables in env_vars
2.) cd into this directory
3.) ./run.sh

The results will be stored in result.txt.

The result is reported as percentage of time it takes to run n threads compared
to run one thread.

n thread
--------   * 100%
1 thread

For example the following lines indicates that it takes between 190-200% of the single thread
execution time to run two threads. Each thread performs the same amount of work.
  <tuple>
    <first>190-200</first><second>2</second>
  </tuple>

The program reports values between the range of 110 percent to 210 percent in 10
percent steps. The program only reports values when the percentage range changes.
Example:
  <tuple>
    <first>130-140</first><second>15</second>
  </tuple>
  <tuple>
    <first>150-160</first><second>17</second>
  </tuple>

Example: The following output shows that performance degrades by between 180-190%
when running 2 threads and between 280-290% when running 3 threads on that
machine.  

...
<integer><mul>
<performance_degradation>
  <tuple>
    <first>190</first><second>2</second>
  </tuple>
  <tuple>
    <first>280-290</first><second>3</second>
  </tuple>
</performance_degradation>
</mul></integer>
...

