SMP support maturity? AMD64x2 or FX-57?

[Frank Mayhar]

Brandon Fosdick wrote:
> SMP support in FreeBSD seems to be a perpetually favorite feature to 
> gripe about, but every release seems to say that its getting better. I'm 
> about to build a new server and am trying to determine if I should go 
> with dual procs or just a single. The AMD64x2 is slightly cheaper than 
> the FX-57 so I'm leaning that way, but it would be a rather pointless 
> savings if SMP isn't well supported.
> So, is SMP in -STABLE ready for primetime? Can it really make use of two 
> processors?

Sigh.  You know, I've been running with two processors since 4.1 or 
thereabouts.  Sure, the BGL scheme is inefficient as far as the kernel 
itself is concerned, but for compute-bound user processes it worked just 
fine.  Naturally I avoided 5.0/1/2 for my production boxen, waiting for the 
complete overhaul of SMP to stabilize, but when I booted 5.3, everything 
was fine and I haven't looked back.

Personally I don't have the first clue what people have found to gripe 
about.  It has been good, it got a _lot_ better in 5.x, and it's continuing 
to improve.

Ports to new processor families are an entirely different kettle of fish 
and have their own sets of problems, virtually all of which have to do with 
the new architecture and not with the general SMP support itself.
-- 
Frank Mayhar frank at exit.com	http://www.exit.com/
Exit Consulting                 http://www.gpsclock.com/
                                 http://www.exit.com/blog/frank/