A simple program that shows the impact of meltdown.

meltdown_test.c

/* a simple program that invokes the kernel */

#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include <linux/random.h>

int main() {

 /* declare our data */
 size_t i,n = 10000000;
 void * random_buffer = NULL;

 random_buffer = malloc(8);

 for(i=0;i<n;i++)
   syscall( SYS_getrandom, random_buffer, 8, GRND_NONBLOCK);

 free(random_buffer);

 return 0;
}

Compile as:
gcc -O1 meltdown_test.c

time run as:
time ./a.out