[OMPI users] OpenSHMEM - Undesired Result !!

[RYAN RAY]

While executing the code in the file exp4.c (Attached) we faced undesired 
result. This code allows all PEs to add a 'quantum' value to a variable 
on a particular host. But in some cases few of these 'quantum' values 
are lost. I have attached the file and a screenshot of the output. In the 
screenshot the last execution is missing 49 quantums. I will be obliged if you 
could explain to me why this is happenning.Regards,Ryan Ray
#include <shmem.h>
#include <stdio.h>
#define quantum 2

static long int total = 0;

int main ( int argc, char ** argv )
{
     int size, rank;
     int i, j, nloop;
     long int my_loc_val = 10000000;    
     
     start_pes(0);
     size=num_pes();
     rank=my_pe();
   
     nloop = my_loc_val/quantum;
     printf("My rank : %d, BEFORE--> My_local_val: %ld, Total: %ld\n", rank, 
my_loc_val, total);

     for(i=0; i<nloop; i++)
     {
         my_loc_val = my_loc_val - quantum;
         shmem_long_add(&total, quantum, 0);
         shmem_quiet();
         //shmem_barrier_all();
     }
     //shmem_barrier_all();   
   
     printf("My rank : %d, AFTER --> My_local_val: %ld, Total: %ld\n", rank, 
my_loc_val, total);
    
 return 0;
}