This repository has been archived on 2022-10-18. You can view files and clone it, but cannot push or open issues or pull requests.
HPC/Project1/project_1_maggioni_claudio/matmult/benchmark.c

175 lines
5.4 KiB
C
Raw Normal View History

2022-09-27 06:35:59 +00:00
#include <stdlib.h> // For: exit, drand48, malloc, free, NULL, EXIT_FAILURE
#include <stdio.h> // For: perror
#include <string.h> // For: memset
#include <float.h> // For: DBL_EPSILON
#include <math.h> // For: fabs
#ifdef GETTIMEOFDAY
#include <sys/time.h> // For struct timeval, gettimeofday
#else
#include <time.h> // For struct timespec, clock_gettime, CLOCK_MONOTONIC
#endif
// On icsmaster
// 2.3 GHz * 8 vector width * 2 flops for FMA = 36.8 GF/s
#define MAX_SPEED 36.8
/* reference_dgemm wraps a call to the BLAS-3 routine DGEMM, via the standard FORTRAN interface - hence the reference semantics. */
#define DGEMM dgemm_
extern void DGEMM (char*, char*, int*, int*, int*, double*, double*, int*, double*, int*, double*, double*, int*);
void reference_dgemm (int N, double ALPHA, double* A, double* B, double* C)
{
char TRANSA = 'N';
char TRANSB = 'N';
int M = N;
int K = N;
double BETA = 1.;
int LDA = N;
int LDB = N;
int LDC = N;
DGEMM(&TRANSA, &TRANSB, &M, &N, &K, &ALPHA, A, &LDA, B, &LDB, &BETA, C, &LDC);
}
/* Your function must have the following signature: */
extern const char* dgemm_desc;
extern void square_dgemm (int, double*, double*, double*);
double wall_time ()
{
#ifdef GETTIMEOFDAY
struct timeval t;
gettimeofday (&t, NULL);
return 1.*t.tv_sec + 1.e-6*t.tv_usec;
#else
struct timespec t;
clock_gettime (CLOCK_MONOTONIC, &t);
return 1.*t.tv_sec + 1.e-9*t.tv_nsec;
#endif
}
void die (const char* message)
{
perror (message);
exit (EXIT_FAILURE);
}
void fill (double* p, int n)
{
for (int i = 0; i < n; ++i)
p[i] = 2 * drand48() - 1; // Uniformly distributed over [-1, 1]
}
void absolute_value (double *p, int n)
{
for (int i = 0; i < n; ++i)
p[i] = fabs (p[i]);
}
/* The benchmarking program */
int main (int argc, char **argv)
{
printf ("#Description:\t%s\n\n", dgemm_desc);
/* Test sizes should highlight performance dips at multiples of certain powers-of-two */
int test_sizes[] =
/* Multiples-of-32, +/- 1. Currently commented. */
/* {31,32,33,63,64,65,95,96,97,127,128,129,159,160,161,191,192,193,223,224,225,255,256,257,287,288,289,319,320,321,351,352,353,383,384,385,415,416,417,447,448,449,479,480,481,511,512,513,543,544,545,575,576,577,607,608,609,639,640,641,671,672,673,703,704,705,735,736,737,767,768,769,799,800,801,831,832,833,863,864,865,895,896,897,927,928,929,959,960,961,991,992,993,1023,1024,1025}; */
/* A representative subset of the first list. Currently uncommented. */
{ 31, 32, 96, 97, 127, 128, 129, 191, 192, 229, 255, 256, 257,
319, 320, 321, 417, 479, 480, 511, 512, 639, 640, 767, 768, 769 };
int nsizes = sizeof(test_sizes)/sizeof(test_sizes[0]);
/* assume last size is also the largest size */
int nmax = test_sizes[nsizes-1];
/* allocate memory for all problems */
double* buf = NULL;
buf = (double*) malloc (3 * nmax * nmax * sizeof(double));
if (buf == NULL) die ("failed to allocate largest problem size");
double Mflops_s[nsizes],per[nsizes],aveper;
/* For each test size */
for (int isize = 0; isize < sizeof(test_sizes)/sizeof(test_sizes[0]); ++isize)
{
/* Create and fill 3 random matrices A,B,C*/
int n = test_sizes[isize];
double* A = buf + 0;
double* B = A + nmax*nmax;
double* C = B + nmax*nmax;
fill (A, n*n);
fill (B, n*n);
fill (C, n*n);
/* Measure performance (in Gflops/s). */
/* Time a "sufficiently long" sequence of calls to reduce noise */
double Gflops_s, seconds = -1.0;
double timeout = 0.1; // "sufficiently long" := at least 1/10 second.
for (int n_iterations = 1; seconds < timeout; n_iterations *= 2)
{
/* Warm-up */
square_dgemm (n, A, B, C);
/* Benchmark n_iterations runs of square_dgemm */
seconds = -wall_time();
for (int it = 0; it < n_iterations; ++it)
square_dgemm (n, A, B, C);
seconds += wall_time();
/* compute Gflop/s rate */
Gflops_s = 2.e-9 * n_iterations * n * n * n / seconds;
}
/* Storing Mflop rate and calculating percentage of peak */
Mflops_s[isize] = Gflops_s*1000;
per[isize] = Gflops_s*100/MAX_SPEED;
printf ("Size: %d\tMflop/s: %8g\tPercentage:%6.2lf\n", n, Mflops_s[isize],per[isize]);
/* Ensure that error does not exceed the theoretical error bound. */
/* C := A * B, computed with square_dgemm */
memset (C, 0, n * n * sizeof(double));
square_dgemm (n, A, B, C);
/* Do not explicitly check that A and B were unmodified on square_dgemm exit
* - if they were, the following will most likely detect it:
* C := C - A * B, computed with reference_dgemm */
reference_dgemm(n, -1., A, B, C);
/* A := |A|, B := |B|, C := |C| */
absolute_value (A, n * n);
absolute_value (B, n * n);
absolute_value (C, n * n);
/* C := |C| - 3 * e_mach * n * |A| * |B|, computed with reference_dgemm */
reference_dgemm (n, -3.*DBL_EPSILON*n, A, B, C);
/* If any element in C is positive, then something went wrong in square_dgemm */
for (int i = 0; i < n * n; ++i)
if (C[i] > 0)
die("*** FAILURE *** Error in matrix multiply exceeds componentwise error bounds.\n" );
}
/* Calculating average percentage of peak reached by algorithm */
aveper=0;
for (int i=0; i<nsizes;i++)
aveper+= per[i];
aveper/=nsizes*1.0;
/* Printing average percentage to screen */
printf("#Average percentage of Peak = %g\n",aveper);
free (buf);
return 0;
}