This example shows the use of PAPI Hardware Performance Counters API with 
pthreads and TAU. It has been tested under Linux. 

% setenv TAU_METRICS TIME:PAPI_FP_INS
% make; simple
% pprof

For 50x50 matrix multiplication, we'd expect 50^3*2 (ax+b is one operation 
on Intel) floating point operations in each multiply loop on each thread. There
are two ways to multiply the matrices. 

If you increase the SIZE, remember that it may exceed the default stack size 
set on your machine (esp. under Linux) (see limit). 

