Re: Can extra processing threads help in this case?

From:
Hector Santos <sant9442@nospam.gmail.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Tue, 23 Mar 2010 01:13:58 -0400
Message-ID:
<etOekekyKHA.5036@TK2MSFTNGP02.phx.gbl>
Hmmmmm, you mean two threads in one process?

What is this:

     num = Data[num]

Do you mean:

    num = Data[i];

Take the posted code I gave you and change this part:

#define USE_STD_VECTOR
#include <vector>

//------------------------------------------------------
// Parameters to play with
//------------------------------------------------------

#define KIND DWORD // array element type
#define MAX_THREADS 64 // # of threads
DWORD nRepeat = 10; // data access repeats
DWORD nTotalThreads = 2; // # of threads
DWORD size = MAXLONG/6; // ~1.4GB
#idef USE_STD_VECTOR
std::vector<KIND> *data = NULL;
#else
KIND *data = NULL;
#endif

//------------------------------------------------------
// Functions to simulate application work load
// The process data function simply reads the
// memory.
//------------------------------------------------------

BOOL AllocateData()
{
    DWORD t1 = GetTickCount();
    _cprintf("- Allocating Data:ram .... ");
#idef USE_STD_VECTOR
     data = new std::vector<KIND>(size);
#else
     data = new KIND[size];
#endif
    _cprintf("%d\n",GetTickCount()-t1);
    return TRUE;
}

void DeallocateData()
{
    if (bUseFileMap) {
       fmdata.Close();
    } else {
       delete data;
    }
}

#pragma optimize("",off)
void ProcessData()
{
    KIND num;
    for(DWORD r = 0; r < nRepeat; r++) {
       for (DWORD i=0; i < size; i++) {
          DWORD j = i;
#idef USE_STD_VECTOR
          num = (*data)[j];
#else
          num = data[j];
#endif
       }
    }
}
#pragma optimize("",on)

And run it with no switches and then /t:2 and /t:4.

WATCH it performs for better!

I would also explore it with USE_STD_VECTOR commented out.

--

Peter Olcott wrote:

The code below apparently proves that you were right all
along.
I ran it as two separate processes and it took a like 16.5
seconds for one instance and 16.55 seconds for two
instances.

"Hector Santos" <sant9442@nospam.gmail.com> wrote in message
news:uwC5O9jyKHA.3884@TK2MSFTNGP06.phx.gbl...

Peter Olcott wrote:

Try running your process again using a
std::vector<unsigned int>
Make sure that you initialize all of this to the
subscript of the init loop.
Make sure that the process monitor shows that the amount
of memory you are allocating is the same amount that
total memory is reduced by.
Make sure that you only use 1/2 of total memory or less.
Make a not of the page fault behavior.
I will try the same thing.


You better! :)

I'll BE BACK!

--
HLS


#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <time.h>

#define uint32 unsigned int

const uint32 repeat = 100;
const uint32 size = 524288000 / 4;
std::vector<uint32> Data;

void Process() {
  clock_t finish;
  clock_t start = clock();
  double duration;
  uint32 num;
  for (uint32 r = 0; r < repeat; r++)
    for (uint32 i = 0; i < size; i++)
      num = Data[num];
   finish = clock();
   duration = (double)(finish - start) / CLOCKS_PER_SEC;
   printf("%4.2f Seconds\n", duration);
 }

int main() {
  printf("Size in bytes--->%d\n", size * 4);
  Data.reserve(size);
  for (int N = 0; N < size; N++)
    Data.push_back(rand() % size);

  char N;
  printf("Hit any key to Continue:");
  scanf("%c", &N);

  Process();

 return 0;
}


--
HLS

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