Re: Utilizing Duo-Core Processors
On Wed, 13 May 2009 03:59:45 -0700 (PDT), hamishd <Hamish.Dean@gmail.com>
wrote:
I have a Intel (R) Core (TM) 2 CPU.
Yes, I see from the thread title you were asking about dual core CPUs.
People don't always read titles, so please include that information in the
thread body as well. :)
So starting 2 threads will achieve what i want?
Lets say I have 10 tasks to process.
Currently i'm going:
void ProcessAll()
{
int nTasks = 10;
for(int ii=0;ii<nTasks;ii++){
ProcessTask(ii);
}
}
How to do the 2 processes?
volatile BOOL T1 = FALSE;
volatile BOOL T2 = FALSE;
UINT ProcessTask1(LPVOID pParam)
{
T1 = TRUE;
DoTask(CurrentTask++);
T1 = FALSE;
return 1;
}
UINT ProcessTask2(LPVOID pParam)
{
T2 = TRUE;
DoTask(CurrentTask++);
T2 = FALSE;
return 1;
}
void ProcessAll()
{
int nTasks = 10;
int CurrentTask = 0;
while(CurrentTask < 10){
if(!T1)
AfxBeginThread(ProcessTask1, this);
if(!T2)
AfxBeginThread(ProcessTask2, this);
}
}
I'm sure the above is not how to do it? What is the standard way?
You need to read up on multithreading. What you're doing above is
completely wrong for multiple reasons, and you need to understand why.
After you've gotten a grip on basic multithreading, see this page for some
necessary info on using CWinThread safely:
http://members.cox.net/doug_web/threads.htm
To briefly answer your question, if you want to start 10 threads, you just
start them. The multiple race conditions in your code will likely lead to
many more than 10 threads being started. (It might be fun to try as an
experiment, but I would recommend maintaining a separate counter in
ProcessAll and break out of the loop if that counter exceeds, say, 100 or
so.) However, as I said in my last message, starting 10 threads to
concurrently perform 10 CPU-intensive tasks on a dual core makes no sense.
--
Doug Harrison
Visual C++ MVP