Thread.BeginThreadAffinity required before WaitHandle calls?

Thread.BeginThreadAffinity required before WaitHandle calls?

• Michael Iacoviello

  Thanks Peter.
  
  Is the threading model an application configuration setting or in some way detectable by the runtime
  
  
  
  

• TheCatty

  As you alluded to, this method is when running in a hosted environment where the current threading model is set to fiber mode.

  Currently, most of the time only SQL Server 2005 hosts the CLR in fiber mode. But, there's no guarentee that a stand-alone application will not be running in a CLR hosted in fiber mode. This method effectively does nothing if the host is not in fiber mode.

  If you're not writing a completly fiber-safe application there's not much point in adding {Begin|End}ThreadAfinity around WaitHandle objects...

  
  
  

• Caleb Widmer

  Using fibers in a host is not supported by the .Net Framework 2.0.

  Even without fibers, a host could move managed code from one Win32 Thread to another which could cause WaitHandle ownership issues.

  Thanks!

  Todd Reifsteck

  SDET, .Net CLR

  
  
  

• jrx

  As far as I can tell, how the host implements threading is an implementation detail of the host. I can see no documented way of configuring the "standard" CLR host to use fibers instead of Win32 threads, or to query the host as to how it has implemented "threads".

  If you want to be safe or support other hosted CLR environments like SQL Server, I would suggest using {Begin|End}ThreadAffinity.

  It's extemely uncommon for programmers to use {Begin|End}ThreadAffinity in "normal" applications.

  
  
  

• Anonymousandmad

  Todd Reifsteck - MSFT wrote:

  Using fibers in a host is not supported by the .Net Framework 2.0. Even without fibers, a host could move managed code from one Win32 Thread to another which could cause WaitHandle ownership issues.

  What framework is SQL Server 2005 using then. MSDN describes several places where it uses fibers for managed threads in "fiber mode":

  http://msdn2.microsoft.com/en-us/library/ms228970.aspx
  http://msdn2.microsoft.com/en-us/library/ms182291.aspx
  http://msdn.microsoft.com/msdnmag/issues/05/06/HyperThreading/default.aspx

  
  
  

• bugduc

  Dino Viehland has an excellent blog that discusses fibers in the .Net Framework 2.0.

  The specific article that mentions that the Framework no longer supports fibers is at http://blogs.msdn.com/dinoviehland/archive/2005/09/15/469642.aspx. This was a late decision in the 2.0 lifecycle and it is very possible that articles that had been written before ~June or July, 2005 still had references to fibers and managed code.

  
  
  

• Steve-x

  j_e_f_f wrote:

  Is the threading model an application configuration setting or in some way detectable by the runtime

  I'm still trying to track that down.
  
  
• Thread.BeginThreadAffinity required before WaitHandle calls?