How to distinguish between physical and virtual CPU cores in Task Manager

[branskyj]

Hi all,
I do lots of 3D rendering and use a lot the "Set Affinity" function in Windows Task Manager to assign some of the CPU cores to my 3D software while keeping other unused for other apps. My question though is how do I distinguish between the physical ad virtual cores in the list in the Task Manager.
I can see there 12 CPU listed ( I have a 3930k CPU) and want to leave one physical and one HT core un-ticked so that I can use them in other apps like Photoshop.
But the task manager doesn't say which is which. So...any ideas?
Thanks.

 

[BrightCandle]

Adjacent cores in task manager (AFAIK) are the same underlying core. So 0,1 and 2,3 form the hyperthreaded grouping.

 

[BonzaiDuck]

Adjacent cores in task manager (AFAIK) are the same underlying core. So 0,1 and 2,3 form the hyperthreaded grouping.

Point of it -- with HT, each physical core is two "virtual cores," and the Affinity feature allows you to park every other one. After that, the virtual core IS the physical core.

 

[Phynaz]

Just let Windows handle your thread scheduling. It's smarter than you are.

 

[Dufus]

As mentioned in another thread you'll have to check your APICID's. This can be different on the same hardware just by using a different version of Windows.

A thread from a few years ago should explain.

http://forums.anandtech.com/showthread.php?t=2118022&page=3

Note to be careful when manually setting affinity and using core parking, results can be detrimental. However in some cases when implemented properly it is possible to obtain better results than relying on the Windows scheduler.

 

[Sequences]

Unless you have a specific technical reason to use core affinity, its better to just let the default scheduler deal with it.

 

[branskyj]

Thanks for the help, guys.
Dufus, I will check the link you provided in just a second.
Phynaz, hurtful man, very hurtful 🙂. No beer for you.

Cheers and take care.

 

[sxr7171]

You can tell because often it will use 0 and 2 much more than 1 and 3.