nopmark.c

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/time.h>

const size_t nop_len = 8L * 1024 * 1024 * 1024; // 8GiB

double time_double()
{
	struct timeval t;
	gettimeofday(&t, NULL);
	return (double)t.tv_sec + (double)t.tv_usec / 1000000;
}

int main()
{
	printf("Initialising NOPmark...\n");
	
	uint8_t *nop_sled = mmap(NULL, nop_len,
		PROT_READ | PROT_WRITE | PROT_EXEC,
		MAP_ANON | MAP_PRIVATE, -1, 0);
	
	if (nop_sled == NULL) {
		perror("mmap");
		return -1;
	}
	
	memset(nop_sled, 0x90, nop_len);
	nop_sled[nop_len-1] = 0xc3;
	
	void (*nop)(void) = (void(*)(void)) nop_sled;
	
	printf("Doing the NOPs...\n");
	double start = time_double();
	nop();
	nop();
	nop();
	nop();
	double duration = time_double() - start;
	printf("Successfully did nothing for %f seconds.\n", duration);
}