Re: Understanding NSPR threads

Wan-Teh Chang wrote, On 2008-07-22 16:55:
> On Tue, Jul 22, 2008 at 7:58 AM, Joachim Ziegler <[email protected]> wrote:
>>  What is a "global bound kernel thread"?
> 
> I suggest that you just use PR_GLOBAL_THREAD.
> 
> NSPR's terminology here is unfortunately incorrect.
> 
> PR_LOCAL_THREAD is a user-level thread scheduled by NSPR
> itself.  Here "local" means such threads contend for CPU time
> within the same process (locally), as opposed to globally with
> the threads in other processes.
> 
> PR_GLOBAL_THREAD is the one that is unfortunately misnamed.
> PR_GLOBAL_THREAD does not mean a "global thread".  It means
> a native thread, which may be a local or global thread.
> 
> Because of this misnaming, we had to add PR_GLOBAL_BOUND_THREAD
> to let our users request specifically a global thread.  The name "BOUND"
> came from the old Solaris thread API, which calls global threads
> "bound threads".
> 
> Note that the two-level thread scheduling is going out of fashion.
> These days all the native thread libraries offer global threads only.
> Global threads are scheduled by the kernel and contend for CPU
> time globally with the threads in the other processes.
> 
> In summary, you should just use PR_GLOBAL_THREAD.  It
> means "give me a native thread, I don't care whether it is a
> local thread or global thread".

Wan-Teh, this post contained information that I have never seen before,
despite having worked with NSPR for over 10 years.  Please put this in
a wiki page, or somewhere where it will be captured for posterity.