#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
typedef long long i64;
long resl; // dt in ticks
float work; // work factor
int dur = 0; // optional delay
static void res(){
  clock_t t0 = clock();
  float nu = 25000000; // nominal work units per second.
  float sc = 500; // normative tick count per sample
  while(t0 == clock()){}
  resl = clock() - t0;
  work = nu*sc/(CLOCKS_PER_SEC/(float)resl);
  printf("resl=%ld, work=%e, CPS = %d\n",
       resl, work, (int)CLOCKS_PER_SEC);}
static i64 Time(){long c = clock(); // Returns time in usec.
  return (1000000LL/CLOCKS_PER_SEC)*c;}
static void T1(int sz, int* a, int msk){int j;
   for(j=0; j<sz; ++j) a[j] = (j^msk);
   for(j=0; j<sz; ++j) if(a[j] != (msk^j)) {
        printf("discrepancy at %d in array of %d bytes\n", j<<2, sz);
        exit(0);}}
static int T2(int sz, int* a, int msk){int j;
   for(j=0; j<sz; ++j) a[j] = (j^msk);
   sleep(dur);
   {i64 t0 = Time();
   for(j=0; j<sz; ++j) if(a[j] != (msk^j)) {
        printf("discrepency at %d in array of %d bytes\n", j<<2, sz);
        exit(0);}
   return Time() - t0;}}
int main(int argc, char ** args){int sz;
  if(argc>2){int siz = atoi(args[1]), m=0;
    dur = atoi(args[2]);
    printf("Will store %d words for %d seconds\n", siz, dur);
    int * a = malloc(4*siz); int c=0;
    while(1) {int d = T2(siz, a, m=m^-1);
        printf("%d good %8.3f swap\n", ++c, d/1000000.);}}
  res();
  if(sizeof(i64) != 8) {printf("Piddling long\n"); exit(0);}
  for(sz = 4; sz*sizeof(int); sz <<= 1) {int * a = malloc(sz*sizeof(int));
   if(!a) {printf("exhausted at %0x\n", sz); exit(0);}
    { int k=work/sz+1, m=k;
      T1(sz, a, k^21); // prime the pump
      if(0) printf("For %d, %d repeats.\n", (int)sz, k);
      {i64 t0 = Time();
        while(k--) T1(sz, a, k^21);
        {double dt = (Time() - t0);
          printf("%d byte array took %e  usec, %3.2f steps/usec\n",
            sz<<2, dt, (double)sz*m/dt);}}}
   free(a);}
  return 0;}