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#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/random.h>
#include <time.h>
#include <math.h>
#define COUNT(x) (sizeof(x) / sizeof(x[0]))
static uint64_t nclock(void)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
return (uint64_t)ts.tv_sec * 1000000000 + ts.tv_nsec;
}
int null(int i, int x, int y);
int ref1(int i, int x, int y);
int ref2(int i, int x, int y);
int new(int i, int x, int y);
int new32(int i, int x, int y);
int new32v2(int i, int x, int y);
int new32v3(int i, int x, int y);
void bigtab_init(void);
int bigtab(int i, int x, int y);
struct solfunc {
const char *name;
int (*func)(int, int, int);
double T, dT;
double adj_T, adj_dT;
};
static struct solfunc solfuncs[ ] = {
{"null", null},
{"ref1", ref1},
{"ref2", ref2},
{"bigtab", bigtab},
{"new", new},
{"new32", new32},
{"new32v2", new32v2},
{"new32v3", new32v3}
};
#define PASSES 5
static void benchmark(void)
{
const int ys[] = {243, 81, 27, 9, 3, 1};
const size_t size = 20*1000*1000;
int seed;
struct { int i, x, y, r; } *data;
struct solfunc *fastest = NULL;
getrandom(&seed, sizeof(seed), 0);
srand(seed);
data = malloc(sizeof(*data) * size);
if (!data) {
fprintf(stderr, "out of memory\n");
exit(2);
}
printf("benchmarking %zu solutions: ", COUNT(solfuncs));
for (size_t j = 0; j < size; j++) {
data[j].i = rand() % 729;
data[j].x = rand() % 3;
data[j].y = ys[rand() % 6];
}
for (size_t i = 0; i < COUNT(solfuncs); i++) {
struct solfunc *sf = solfuncs + i;
double ts[PASSES], var;
printf("%zu", i + 1);
for (size_t j = 0; j < PASSES; j++) {
uint64_t t0;
fflush(stdout);
t0 = nclock();
for (size_t k = 0; k < size; k++)
data[k].r = sf->func(data[k].i, data[k].x,
data[k].y);
ts[j] = (nclock() - t0) * 1.0e-9;
ts[j] *= 1.0e9 / size;
printf(".");
}
sf->T = 0.0f;
for (size_t j = 0; j < PASSES; j++)
sf->T += ts[j];
sf->T /= PASSES;
var = 0.0f;
for (size_t j = 0; j < PASSES; j++)
var += pow(ts[j] - sf->T, 2.0);
sf->dT = sqrt(var) / sqrt(PASSES);
}
printf("\n");
for (size_t i = 1; i < COUNT(solfuncs); i++) {
struct solfunc *sf = solfuncs + i;
sf->adj_T = sf->T - solfuncs[0].T;
sf->adj_dT = sqrt(pow(sf->dT, 2) + pow(solfuncs[0].dT, 2));
if (!fastest || sf->T < fastest->T) {
fastest = sf;
fastest->T = sf->T;
}
}
for (size_t i = 0; i < COUNT(solfuncs); i++) {
struct solfunc *sf = solfuncs + i;
printf("%7s %.2f ± %.2f", sf->name, sf->T, sf->dT);
if (i > 0) {
printf(" (x %.3f)", sf->T / fastest->T);
printf(" %.2f ± %.2f", sf->adj_T, sf->adj_dT);
printf(" (x %.3f)", sf->adj_T / fastest->adj_T);
}
puts("");
}
}
int main(void)
{
bigtab_init();
for (int j = 2; j < COUNT(solfuncs); j++) {
struct solfunc *sf = solfuncs + j;
for (int i = 0; i < 729; i++)
for (int x = 0; x < 3; x++)
for (int y = 243; y > 0; y /= 3) {
int ref, res;
ref = ref1(i, x, y);
if ((res = sf->func(i, x, y)) != ref) {
printf("\n%s fails for %i/%i/%i: got %i, expected %i\n",
sf->name, i, x, y, res, ref);
return 1;
}
}
}
benchmark();
return 0;
}
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