[zenom@lynx c]$ cat overcommit.c
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <assert.h>
#include <time.h>

#define NKEYS 9000000

int main(int argc, char** argv) {
  int i;
  clock_t start, end;
  uint32_t* collection = calloc(UINT32_MAX, sizeof(uint32_t));

  printf("Put %d uint32_t values...", NKEYS);
  start = clock();

  for (i = 0; i < NKEYS; i++)
    collection[i] = 42;
  end = clock();
  printf("took %.5f seconds\n", (end - start) / (double) CLOCKS_PER_SEC);

  printf("Retrieve %d uint32_t values...", NKEYS);
  start = clock();

  for (i = 0; i < NKEYS; i++)
    assert(collection[i] = 42);
  end = clock();
  printf("took %.5f secondds\n", (end - start) / (double) CLOCKS_PER_SEC);
}

[zenom@lynx c]$ sudo sysctl vm.overcommit_memory=1
[sudo] пароль для zenom:
vm.overcommit_memory = 1

[zenom@lynx c]$ gcc overcommit.c

[zenom@lynx c]$ ./a.out
Put 9000000 uint32_t values...took 0.13819 seconds
Retrieve 9000000 uint32_t values...took 0.02524 secondds
[zenom@lynx c]$