Strawman proposal: making libthr default thread implementation?

[Daniel Eischen]

On Mon, 3 Jul 2006, Robert Watson wrote:

>
> I know this has been discussed in the past, but I figured with 7.x trundling 
> forward, it was time to think about it again.  In benchmarks for many common 
> applications and scenarios, libthr demonstrates significantly better 
> performance over libpthread -- this is not a coincidence, as David Xu has 
> invested a lot of time in improving libthr and application performance, and 
> libthr has benefitted significantly from the last ten years of threading work 
> on FreeBSD.  libthr is also implemented across a larger number of our 
> platforms, and is already libpthread on several.  The first recommendation we 
> make to MySQL and other heavy thread users is "Switch to libthr", which is 
> suggestive, also!  Likewise, I know David has worked hard to eliminate 
> technical and standards obstacles that have been raised in the past.  This 
> e-mail is a strawman proposal, intended to raise discussion, and possibly 
> lead to action.
>
> So the strawman proposal is: make libthr the default threading library on 
> 7.x. A few questions given the proposal:
>
> - Are there technical features present in libpthread that aren't yet in
>  libthr, and are required?  In the past system/local thread support has been
>  the complaint, but I believe that is now long fixed.  This is useful
>  regardless of a switch.

Yes, you have to support PTHREAD_PRIO_PROTECT, PTHREAD_PRIO_INHERIT
mutexes, and SCHED_RR, SCHED_FIFO, and SCHED_SPORADIC scheduling
(hopefully not under the restriction that you are a privileged user).

If you can those in libthr, I have no objection.  However, these
are not as easy to do in 1:1.

-- 
DE