Many instances run on many cores?

[anhnha]

I have a problem and need some help.e
For example, I have an MFC app for image processing written in C++.
Let's say that this app only run on one core when only one instance is opened.
When I open many instances of this app, does each instance run on each separate core?

[fries100]

No but you can set affinity to run on a desired core.

Right click the process in the task manager and set it there or run it from cmd:

C:\Windows\System32\cmd.exe /C start /affinity 1 yourprogram.exe
C:\Windows\System32\cmd.exe /C start /affinity 2 yourprogram.exe
.....

[Texan40]

You can also look at SetThreadAffinityMask() : https://msdn.microsoft.com/en-us/library/windows/desktop/ms686247%28v=vs.85%29.aspx

Edit: also reading over http://stackoverflow.com/questions/5919699/proper-usage-of-setthreadaffinitymask wouldn't hurt

[anhnha]

Thank you!
I have a question.
Let's say I have an image processing application and I need to process an image I.
With only one instance this takes 10s.
With two identical instances running on two cores at the same time. Assuming that each instance process the image I. How long does it takes for each instance to process I in this case?
Does it instance also take 10s to finish?

[xcomwarr]

Just too stupid question to even bother about. Answers are two same image ONE is with more 1.2+1.2=2.4Ghz so I suggest to work on process optimization and copy same code for second core.