lab/lcdbench/lcdbench.c
2021-06-01 02:31:53 +09:00

64 lines
1.5 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <time.h>
const int width = 800;
const int height = 480;
// 1 loop = 2 draws
// 30 loop = 60 draws = 1 sec (60 fps)
const int nloop = 30 * 3;
struct timespec diff(struct timespec start, struct timespec end);
int main(void) {
FILE *f;
uint16_t buf1[width * height]; //RGB565
uint16_t buf2[width * height];
struct timespec ts1, ts2, d;
int i, j;
float elapsed;
for (i = 0; i < height; i++) {
for (j = 0; j < width; j++) {
buf1[i * width + j] = (i << 8) + j;
buf2[i * width + j] = ~((i << 8) + j);
}
}
f = fopen("/dev/fb0", "w");
if (f == NULL) {
printf("Could not open /dev/fb0\n");
return 1;
}
clock_gettime(CLOCK_MONOTONIC, &ts1);
for (j = 0; j < nloop; j++) {
fwrite(buf1, sizeof(buf1), 1, f);
fseek(f, 0, SEEK_SET);
fwrite(buf2, sizeof(buf2), 1, f);
fseek(f, 0, SEEK_SET);
}
clock_gettime(CLOCK_MONOTONIC, &ts2);
d = diff(ts1, ts2);
elapsed = (float)d.tv_sec + ((float)d.tv_nsec * 1e-9);
printf("Frames: %d\n", nloop * 2);
printf("Elapsed: %f\n", elapsed);
printf("Frames per second: %f\n", (float)(nloop * 2) / elapsed);
}
// https://www.guyrutenberg.com/2007/09/22/profiling-code-using-clock_gettime/
struct timespec diff(struct timespec start, struct timespec end) {
struct timespec temp;
if ((end.tv_nsec-start.tv_nsec)<0) {
temp.tv_sec = end.tv_sec-start.tv_sec-1;
temp.tv_nsec = 1000000000+end.tv_nsec-start.tv_nsec;
} else {
temp.tv_sec = end.tv_sec-start.tv_sec;
temp.tv_nsec = end.tv_nsec-start.tv_nsec;
}
return temp;
}