write_to_ram_warm.c

#define _GNU_SOURCE

#include<stdio.h>
#include<unistd.h>
#include<fcntl.h>
#include<time.h>
#include<string.h>
#include<malloc.h>
#include<stdlib.h>
#include<sys/mman.h>

#define END_SIZE	(64UL * 1024 * 1024) 

const int start_size = 512;

int main(int argc, char **argv)
{
	int fd, i;
	long long time;
	unsigned long long FILE_SIZE;
	size_t len;
	off_t offset;
	char c = 'a';
	char unit;
	struct timespec start, end;
	int size;
	unsigned long long count;
	void *buf1 = NULL;
	char *buf;
	FILE *output;
	char fs_type[20];
	char xip_enabled[20];
	char quill_enabled[20];
	char file_size_num[20];
	char filename[60];

	if (argc < 6) {
		printf("Usage: ./write_to_ram $FS $XIP $Quill $FILE_SIZE $filename\n");
		return 0;
	}

	strcpy(fs_type, argv[1]);

	if (!strcmp(argv[2], "0"))
		strcpy(xip_enabled, "No_XIP");
	else
		strcpy(xip_enabled, "XIP");

	if (!strcmp(argv[3], "0"))
		strcpy(quill_enabled, "Posix");
	else
		strcpy(quill_enabled, "Quill");

	strcpy(file_size_num, argv[4]);
	len = strlen(file_size_num);
	unit = file_size_num[len - 1];
	file_size_num[len - 1] = '\0';
	FILE_SIZE = atoll(file_size_num);
	switch (unit) {
	case 'K':
	case 'k':
		FILE_SIZE *= 1024;
		break;
	case 'M':
	case 'm':
		FILE_SIZE *= 1048576;
		break;
	case 'G':
	case 'g':
		FILE_SIZE *= 1073741824;
		break;
	default:
		printf("ERROR: FILE_SIZE should be #K/M/G format.\n");
		return 0;
		break;
	}

	if (FILE_SIZE < 4096)
		FILE_SIZE = 4096;
	if (FILE_SIZE > 2147483648) // RAM disk size
		FILE_SIZE = 2147483648;

	strcpy(filename, argv[5]);
	output = fopen(filename, "a");

	if (posix_memalign(&buf1, END_SIZE, END_SIZE)) { // up to 64MB
		printf("ERROR - POSIX NOMEM!\n");
		return 0;
	}

	buf = (char *)buf1;
	fd = open("/mnt/ramdisk/test1", O_CREAT | O_RDWR | O_DIRECT, 0640); 
//	fd = open("/dev/null", O_CREAT | O_RDWR | O_DIRECT, 0640); 

//	for (size = start_size; size <= END_SIZE; size <<= 1) {
	size = 4096;
		memset(buf, c, size);
		c++;
		lseek(fd, 0, SEEK_SET);
		offset = 0;

		// Warm the cache
		for (i = 0; i < 262144; i++) {
			if (pwrite(fd, buf, size, offset) != size)
				printf("ERROR!\n");
			offset += size;
		}

		lseek(fd, 0, SEEK_SET);
		count = FILE_SIZE / size;
		offset = 0;
		
		clock_gettime(CLOCK_MONOTONIC, &start);
//			pread(fd, buf, size);
		clock_gettime(CLOCK_MONOTONIC, &end);

		time = (end.tv_sec - start.tv_sec) * 1e9 + (end.tv_nsec - start.tv_nsec);
		printf("Write: Size %d bytes,\t %lld times,\t %lld nanoseconds,\t latency %lld nanoseconds, \t Bandwidth %f MB/s.\n", size, count, time, time / count, FILE_SIZE * 1024.0 / time);
		fprintf(output, "%s,%s,%s,%d,%lld,%lld,%lld,%f\n", fs_type, quill_enabled, xip_enabled, size, FILE_SIZE, count, time, FILE_SIZE * 1.0 / time);
//	}

	fclose(output);
	close(fd);
	free(buf1);
	return 0;
}