libthr and 1:1 threading.

[Peter Wemm]

Terry Lambert wrote:
> Jun Su wrote:
> > 
> [ ... 1:1 kernel threads implementation ... ]
> > 
> > A benchmark would be interested.
> 
> This request doesn't make sense.
> 
> The primary performance reasoning behind a 1:1 kernel threading
> implementation, relative to the user space single kernel entry
> scheduler in the libc_r implementation is SMP scalability for
> threaded applications.

No.  It gives the ability for a thread to block on a syscall without
stalling the entire system.  Just try using mysqld on a system using libc_r
and heavy disk IO.  You can't select() on a read() from disk.  Thats the
ultimate reason to do it.  The SMP parallelism is a bonus.

Cheers,
-Peter
--
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5