Question

My VC++ 2010 express install time has expired so i cant use it anymore without changing the date from right-down. I dont want to do this so i am asking you these questions:

Do you think, below multi-threaded program’s threads working in an order?

What if i put similar 3 more threads to calculate next-1000 particles, does the contet-switches become exhausting or just the Sleep(10)s are exhausting?

Note: Each calculation(each one of force,vel., pos.) takes about 9 ms.

Something like this:
core1:first 1000 particles forces     //
core2:first 1000 particles velocities //===>these 3 are connected
core3:first 1000 particles positions  // ------------------------------
                                                                      |
core4:next 1000 particles forces      //                               ====these 2 will be connected
core5:next 1000 particles velocities  //===>these 3 are connected     |
core6:next 1000 particles positions   // ------------------------------

boolean locker1;
boolean locker2;
boolean locker3;

boolean worker1;
boolean worker2;
boolean worker3;

void core1(void * x)
{
    while(worker1)
    {
         while(!locker1){Sleep(10);}
         for(int i=0;i<1000;i++)
         {
              //calculate 1000 particles forces
         }
         locker2=true; //starts core2 thread
         while(locker2){Sleep(10);} //core2 must be working
         while(locker3){Sleep(10);} //core3 must be working
    }
   _endthread();
}

void core2(void * y)
{
    while(worker2)
    {
         if(!locker2){Sleep(10);}
         for(int i=0;i<1000;i++)
         {
              //calculate 1000 particles velocities
         }
         locker3=true; //starts core3 thread
         while(locker3){Sleep(10);} //core3 must be working
         while(locker1){Sleep(10);} //core1 must be working
    }
   _endthread();

}

void core3(void * z)
{
    while(worker3)
    {
         if(!locker3){Sleep(10);}
         for(int i=0;i<1000;i++)
         {
              //calculate 1000 particles positions
         }
         locker1=true; //starts core1 thread
         while(locker1){Sleep(10);} //core1 must be working
         while(locker2){Sleep(10);} //core2 must be working
    }
   _endthread();

}

int main()
{
    locker1=false; 
    locker2=false;
    locker3=false;
    worker1=true; 
    worker2=true;
    worker3=true;
    _beginthread(core1,0,(void *)0);
    _beginthread(core2,0,(void *)0);
    _beginthread(core3,0,(void *)0);

    locker1=true; //gets the waiting core1-thread working
                  //so i think when it finishes, it releases core2 to work
                  //when core2 finishes, core3 starts working

    Sleep(100);
    worker1=false;
    worker2=false;
    worker3=false; //after a while i shut them down

}

Please if any one having VC++ could give me some hints or suggestions i appreciate.

Or should i just forget the 3+3-->2 system and do this(6)? :

core1 first 233 particles for computing forces ----->all for velocity ----->all for psoition
core2 next 233 particles for computing forces ----->all for velocity ----->all for psoition
core3 next 233 particles for computing forces ----->all for velocity ----->all for psoition
core4 next 233 particles for computing forces ----->all for velocity ----->all for psoition
core5 next 233 particles for computing forces ----->all for velocity ----->all for psoition
core6 last 233 particles for computing forces ----->all for velocity ----->all for psoition

and just wait all of them finish to get to next calculation?

Answer 1

“Do you think, below multi-threaded program’s threads working in an order?”

Not at all. You violate way too many rules on multi-threaded programming.

Also, the point of threads is to execute things in parallel. If you need to do A, B and C in sequence, do them in the same thread.