Re: How to limit number of CPU cores used by a Cocoa app

FROM : Mike Abdullah
DATE : Sat Jan 05 13:57:56 2008

On 5 Jan 2008, at 12:02, Andre Schnoor wrote:

> Dave Camp wrote:

>> On Dec 30, 2007, at 3:14 AM, Andre Schnoor wrote:

>>> Chris Hanson wrote:

>>>> Why do you think restricting threads to run on only 2 cores will 
>>>> be useful?

>>>
>>> I observed problems with GUI threads when running the app on an 8-
>>> core Mac Pro, while it runs fine on dual core CPUs and PPC.  The 
>>> fix is intented as a temporary workaround only until I found the 
>>> real cause.

>>
>> That's your problem. All of your GUI (with a few exceptions) needs 
>> to be on the main thread.
>>

>
> I understand. But why is the method that forks a drawing thread 
> called #detachDrawingThread:toTarget:withObject: in the first place? 
> IMHO, this is misleading.
>
> If the detached thread (which currently initiates all of my graphics 
> output, except window and menu creation) is not allowed to do any UI 
> drawing, then it should not be called a "drawing" thread. Apple 
> should mention this in the documentation clearly.


This is true, but the docs clearly state that that method is just a 
convenience for +detachNewThreadSelector:toTarget:withObject:

You can do some drawing on a background thread if you wish. 
NSProgressIndicator does it for a start. BUT you have to be VERY 
careful to properly lock the view you are drawing into so that nothing 
goes wrong.

Mike.