1:1 Threading implementation.

[Scott Long]

Robert Watson wrote:
> On Tue, 25 Mar 2003, Jeff Roberson wrote:
> 
> 
>>Thanks to the foundation provided by Julian, David Xu, Mini, Dan
>>Eischen, and everyone else who has participated with KSE and libpthread
>>development Mini and I have developed a 1:1 threading implementation. 
>>This code works in parallel with KSE and does not break it in any way. 
>>It actually helps bring M:N threading closer by testing out shared bits. 
> 
> 
> My feeling is that this is an excellent strategy to get us productionable
> kernel-supported threads for the upcoming 5.x release while permitting
> continued R&D (and I think it is R&D) into the M:N threading
> possibilities.  One nice thing about this construction is that the cost
> was very low given the existing investment in KSE, yet the payoff is very
> high.  And it will provide a nice migration path when KSE is
> productionable for sites interested in doing that: thread-reliant
> applications will no longer be explicitly linked against a non-native
> threading package (linuxthreads), which is the status quo for large
> threaded applications on FreeBSD right now.  So it seems to me that a
> relatively straight-forward strategy gets things moving:
>  [...]

I'd like to add a big 'Me too' here also.  1:1 gives us an excellent
milestone towards having KSE work for 5-STABLE.  The June 30 deadline
for KSE has been quickly approaching, and this work achieves all of
the minimum objectives that we were aiming for by that date.  I see
this as a win-win for everyone; application threading is vastly
improved, the existing KSE work gets real-world
testing/exposure/validation, and the M:N work can now procede without
any of the pressure and stress that it had before.

In the spirit that FreeBSD is as much for research as it is for
production, it's important to remember that M:N should be kept around
and a research project through the RELENG_5 branch and into 6-CURRENT.
Once it is stable and proven, we can look at backporting it into
5-STABLE.

Overall, I'm incredibly pleased by this work!  This is a major milestone
for 5-STABLE, and one that will make it a worthwhile branch.

Scott