Processor greedy program

I have converted a C dos program to VC++ the program works Ok but it uses up all the processor resources and therefore stops timers I am using to control events.  I have done this for a final year dissertation and I have to explain why this is happing.  Does any one have any ideas or has anyone come across a site  which explains how processor resources are allocated.  I thought that as it is programed in VC++ it should have the time sharing ability of windows.
LVL 1
Richard_EustaceAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

IexpertCommented:
? Windoze what?
emm something else, oh yes show the bit of
code that's using the resources!!!!!!!!
0
nietodCommented:
In windows you want to avoid code that does "bussy waiting", like loops that continually check to see of a key has been typed or that checks to see if some flag has been set.  Windows provides lots of different options for avoiding those sorts of busy waits, but we would need to know more details about your program in order to tell you what to do.

>> explains how processor resources are allocated.
This is very complex in windows because it is a mix of pre-emptive and cooperative mult-tasking.  If it was strictly pre-emptive this probably would not be as big a problem.   I recommend you loo at some opf the windows "internals" books, like "Inside Windows 95" for a description of how the multi-tasking works in windows 9x.
0
tdubroffCommented:
You can put any wait-for-somethings that you have inside a thread, or you can manually force the Windows Message Pump to keep pumping messages.  To do this you could insert this code inside your wait-for-something routines:

    MSG Message;

    if (::PeekMessage(&Message,NULL,0,0,PM_REMOVE)){
        ::TranslateMessage(&Message);
        ::DispatchMessage(&Message);
    }

Every time this code is called, Windows gets a chance to dispatch a waiting message.  Call it multiple times so that Windows keeps getting a chance for dispatches.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Cloud Class® Course: Certified Penetration Testing

This CPTE Certified Penetration Testing Engineer course covers everything you need to know about becoming a Certified Penetration Testing Engineer. Career Path: Professional roles include Ethical Hackers, Security Consultants, System Administrators, and Chief Security Officers.

nietodCommented:
Since this is a converted DOS program, it probably doesn't have a message pump--or need for one.
0
pellepCommented:
You might try putting a Sleep(50) (or another short period of time) somewhere in your loop to yield execution to ther threads.
0
nietodCommented:
That can help in a sense, but win32 is pre-emptive, so you don't want to do that when your program has work to do.  Ans it would be best if you didn't use any CPU time when there is not work to do.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
C++

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.