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?
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@exit.com http://www.exit.com/ Exit Consulting http://www.gpsclock.com/ http://www.exit.com/blog/frank/
On Friday 22 July 2005 04:06 pm, 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? _______________________________________________I'm running RELENG_6 on a dual processor Opteron in 64 bit mode and it's working fine as long as I'm using the 4BSD scheduler. -- Anish Mistry -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 187 bytes Desc: not available Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20050722/1f22bba8/attachment.bin
> 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.Well, I've not triied it under amd64, but i386 SMP has been rock stable for me since I upgraded to 5.X, on both nyperthreaded machines and genuine SMP machines. Choosing one or two cores is, however, more a matter of what the box is going to be doing - if you are usually running one big compute job then a single faster core is better than two smaller ones.> So, is SMP in -STABLE ready for primetime? Can it really make use of two processors?Yes and yes. -pcf.