CODEWITHSUNDEEP
c#multithreadingwinforms
user4032346
user4032346

Reputation: 409

Does a single threaded application run on only one CPU

I am developing a single threaded application on an 8 CPU machine and when a heavy operation happens the CPU utilization appears like this :

enter image description here

Does the .NET framework have some facility to divide the work of that single thread (automatically) into the other CPUs ?

Upvotes: 6

Views: 3094

Answers (7)

Baptiste Chardon
Baptiste Chardon

Reputation: 54

I know that this is an old thread, but I arrived here with the same problem, and a different cause/solution.

If you launch your program through the Visual Studio Debugger (VS2012 here), it seems that your threads are bound to a single core. In order to use all the cores available, I had to launch it directly from the executable or from a windows cmd prompt.

May be very specific, but hope it helps.

Upvotes: 0

Stephen Cleary
Stephen Cleary

Reputation: 457147

Does a single threaded application run on only one CPU?

As others have noted, not necessarily. However, a given thread will only run on one core at a time.

Does .net framework have some facility to divide the work into the other CPUs?

Yes. .NET has the Parallel class and Parallel LINQ. Note that you have to divide up the work yourself (into small pieces), and then the .NET framework will handle balancing the work between multiple threads automatically.

Upvotes: 5

Denis Itskovich
Denis Itskovich

Reputation: 4543

It's not guaranteed that any single thread will always run on the same core. But it's guaranteed that it will run only on one core at the same time. But it can run on one core till context switch, and resume after the context switch on another core. Each time-slice, your thread gets, may be allocated on another core.

Upvotes: 9

Oakcool
Oakcool

Reputation: 1496

No it will always run in one processor/core, and it might change depending on the scheduler.

You can also use async and await, and they will help with the fluidity of you application.

Have you looked into Task, its a very simple way of creating threads

Task.Run(() =>
{
    // Do something that will take a long time
    Thread.Sleep(10000);
});

Upvotes: -1

Peter Duniho
Peter Duniho

Reputation: 70701

Even a process with just one thread may or may not always run that one thread on the same CPU. The total CPU utilization for that process cannot exceed 100% of a single core, of course. But that 100% may be spread across as many cores as there are on the machine. So you may see e.g. 50% utilization on two different cores instead of 100% on just one, 25% on four different cores, etc.

Upvotes: 3

David Morales
David Morales

Reputation: 57

A single threaded application only runs on one core of your CPU so the way it works is when you have multiple CPU's your just getting more cores making your pc more powerful. Your only using one core on all of the CPU's.

Upvotes: 1

Nick Strupat
Nick Strupat

Reputation: 5063

The .NET garbage collector will run on another thread, the GUI will if you're doing WinForms/WPF, and the OS will be doing all kinds of work in other threads to help your single-threaded app run faster.

Upvotes: 1

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