Disk speed test simulating CinePi

test_speed_multi.c

#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <sys/resource.h>

#define BLOCK_SIZE 4096
#define FILE_SIZE (30 * 1024 * 1024)  // 30 MB, which is a multiple of BLOCK_SIZE
#define NUM_FILES 50

int main(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <destination_directory>\n", argv[0]);
        return 1;
    }

    char *dest_dir = argv[1];
    int fd;
    char *buffer;
    ssize_t bytes_written;
    struct timespec start, end;

    // Allocate aligned memory for O_DIRECT for the entire file size
    if (posix_memalign((void **)&buffer, BLOCK_SIZE, FILE_SIZE) != 0) {
        perror("Error allocating aligned memory");
        return 1;
    }
    memset(buffer, 'A', FILE_SIZE);

    struct rusage usage_start, usage_end;
    getrusage(RUSAGE_SELF, &usage_start);

    clock_gettime(CLOCK_MONOTONIC, &start);

    for (int i = 0; i < NUM_FILES; i++) {
        char filename[256];
        snprintf(filename, sizeof(filename), "%s/testfile_%04d.dat", dest_dir, i);

        fd = open(filename, O_WRONLY | O_CREAT | O_DIRECT, 0644);
        if (fd == -1) {
            perror("Error opening file");
            free(buffer);
            return 1;
        }

        bytes_written = write(fd, buffer, FILE_SIZE);
        if (bytes_written != FILE_SIZE) {
            perror("Error writing to file");
            close(fd);
            free(buffer);
            return 1;
        }

        close(fd);
    }

    clock_gettime(CLOCK_MONOTONIC, &end);
    free(buffer);

    getrusage(RUSAGE_SELF, &usage_end);

    double elapsed = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1e9;
    //double speed = (FILE_SIZE * NUM_FILES) / (1024 * 1024) / elapsed;
    double speed = ((long long)FILE_SIZE * NUM_FILES) / (1024.0 * 1024.0) / elapsed;
    //printf("Total data written: %d MB\n", (FILE_SIZE * NUM_FILES) / (1024 * 1024));
    printf("Total data written: %lld MB\n", ((long long)FILE_SIZE * NUM_FILES) / (1024 * 1024));
    printf("Time taken: %.2f seconds\n", elapsed);
    printf("Write speed: %.2f MB/s\n", speed);


double user_cpu_time_used = (usage_end.ru_utime.tv_sec - usage_start.ru_utime.tv_sec) +
                                (usage_end.ru_utime.tv_usec - usage_start.ru_utime.tv_usec) / 1e6;
    double system_cpu_time_used = (usage_end.ru_stime.tv_sec - usage_start.ru_stime.tv_sec) +
                                  (usage_end.ru_stime.tv_usec - usage_start.ru_stime.tv_usec) / 1e6;

    printf("User CPU time used: %.2f seconds\n", user_cpu_time_used);
    printf("System CPU time used: %.2f seconds\n", system_cpu_time_used);

    return 0;
}

gcc test_speed_multi.c -o test_speed_multi -lrt