cycler -- cycles per time

cycler.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <time.h>

#define BUFSIZE 2<<15 

char buforig[BUFSIZE];
char bufcopy[BUFSIZE];

char testname[512] = "no active test";
clock_t start = 0;
int cycles = 0;

int randomize(char *buffer, size_t len)
{
	FILE *urandom = fopen("/dev/urandom", "r");
	if (urandom == NULL)
		return -1;
	if (fread(buffer, 1, len, urandom) != len)
		return -1;
	return 0;
}

int cycle(double secs, int (*cb)(const void*, const void*, size_t),
		void *arg1, void *arg2, size_t num)
{
	clock_t end;
	start = clock();
	end = start + (secs * CLOCKS_PER_SEC);
	cycles = 0;
	while (clock() < end && ++cycles) {
		(*cb)(arg1, arg2, num);
	}
	return cycles;
}

void info(int parameter)
{
	printf("[%5.1fs]%43s: %10d cycles\n",
		(clock() - start) / (float)(CLOCKS_PER_SEC), testname, cycles);
}

int main(int argc, char *argv[])
{
	double secs = 5;

	if (randomize(buforig, BUFSIZE) < 0) {
		fprintf(stderr, "couldn't read from /dev/urandom\n");
		return 1;
	}
	memcpy(bufcopy, buforig, BUFSIZE);

	if (argc > 1) {
		secs = strtod(argv[1], NULL);
	}

	signal(SIGTSTP, info);

	printf("cycling for %.2f seconds ..\n", secs);

	sprintf(testname, "memcmp(%p, %p, %d)", buforig, buforig, BUFSIZE);
	cycle(secs, memcmp, buforig, buforig, BUFSIZE);
	info(0);

	sprintf(testname, "memcmp(%p, %p, %d)", buforig, bufcopy, BUFSIZE);
	cycle(secs, memcmp, buforig, bufcopy, BUFSIZE);
	info(0);

	return 0;
}