Thread.SetProcessorAffinity Method
Note
This method is available only when developing for the Xbox 360.
Sets the processor affinity for a managed thread. Processor affinity determines the processors on which a thread runs.
Namespace: System.Threading
Assembly: mscorlib (in mscorlib.dll)
Syntax
public void SetProcessorAffinity (
params int[] cpus
)
Parameters
cpus
An array of identifiers that specify the hardware threads on which the managed thread is permitted to run.For Xbox 360, only a single hardware thread can be specified—the cpus array should contain only one element. The hardware thread number must be in the range 0 through 5.
XNA Game Studio Express games should not use hardware threads 0 or 2; see Remarks below.
Exceptions
| Exception type | Condition |
|---|---|
| InvalidOperationException | An invalid value was passed to the method. |
Remarks
Each of the Xbox 360's three CPU cores has two hardware threads; the hardware thread number selects a specific hardware thread on a specific core. Hardware threads 0 and 1 are the hardware threads on core 0; 2 and 3 are the hardware threads on core 1; and 4 and 5 are the hardware threads on core 2.
| Hardware Thread Number | Core |
|---|---|
| 0 or 1 | 0 |
| 2 or 3 | 1 |
| 4 or 5 | 2 |
Xbox 360 software threads are associated with, and run on, only a single hardware thread at a time. The hardware thread on which a thread runs (the thread's processor affinity) must be set to a single hardware thread, but can be subsequently changed by calling SetProcessorAffinity with a different hardware thread number. When a thread is created, it is initially assigned to the current hardware thread (that is, the hardware thread on which the current thread is running).
For Xbox 360 threads, you cannot clear the thread's processor affinity by passing an empty array as the cpus parameter. An Xbox 360 thread will always be associated with one hardware thread.
XNA Game Studio Express games should not use hardware threads 0 or 2, which are reserved for the XNA Framework. The following table identifies Xbox 360 hardware thread usage.
| Hardware Thread | Available |
|---|---|
| 0 | No, reserved for XNA Framework. |
| 1 | Yes |
| 2 | No, reserved for XNA Framework. |
| 3 | Yes |
| 4 | Yes |
| 5 | Yes |
To determine the number of hardware threads supported by the hardware, use System.Environment.ProcessorCount.
This method should not be used with threads created by the ThreadPool or Timer classes.
See Also
Tasks
How to: Create and Terminate Threads (C# Programming Guide)
Concepts
Threading (C# Programming Guide)
Using Threading (C# Programming Guide)
Reference
Thread Class
Thread Members
System.Threading Namespace
System.Environment.ProcessorCount Method
Platforms
Xbox 360