Linux Gains Support for NUMA

soosterh writes "CNet has an article about a NUMA patch from IBM. It says that the improvement adds some support in Linux for nonuniform memory access, or NUMA, a design for higher-end servers with many processors. Linus Torvalds, the original creator of the operating system and still its top authority, accepted the update this month into version 2.5, the current test version of the software."

Comments

Not just for big iron

[awptic]

Not only is this beneficial for large computers, but also on smaller SMP systems with hyperthreading. On CPU's with hyperthreading,
it's often faster for a process to reside on the same CPU but not necessary the same 'virtual' CPU when accessing memory.
And alot of 8way+ systems are NUMA whether or not they are advertised as such.

Re:Not just for big iron

[be-fan]

Actually, the previous 2.5 scheduler handled hyperthreading just fine. The real draw is that this new patch makes hyperthreading just a subset of NUMA, which makes things much cleaner.

Re:Linux lacks democracy

[Anonymous Hack]

Of course, until you show why your stream is better than the main stream, you'll be pretty lonely on your fork.

Unfortunately it's not JUST showing someone you're better, it's "marketing" too. That's pretty hard in the case of Linux, because you can't use the name "Linux" anywhere - it's trademarked by Linus. If i made some funkyass Linux fork and called it Finnix, it wouldn't get the press Linux would, and you'd effectively be ten years back in time, building up a name etc. With BSD it's a little easier, because "BSD" in and of itself isn't trademarked, though it's doubtful whether you'd be able to get away with calling your Soviet Russia fork "NyetBSD".

That said, i pretty much agree. Linux has so much stuff in it right now as a kernel (in the sense of running on a zillion architectures with a zillion features) i'd say Linus is pretty much pleasing everyone in the end. Most Alan Cox stuff gets rolled in, most commercial stuff does too. It's all good.

Re:ram question then

[jericho4.0]

If the NUMA patch can handle latencies on the order of a few milliseconds, you might be able to use this to safely fool your kernel into thinking you have 120 gigs of RAM (from storage).

Of course, actually doing this would involve jumping through a few hoops, and I have to think hard to come up with situations why this would be the way to go.

Gees, any MB I've bought in the last several years can take more RAM than I'm willing to buy for it. I wonder what kind of memory limits the OP was asking about.

SGI must have added NUMA support as well

[Anonymous Coward]

Hi,

SGI must have added NUMA support for their Itanium-based Altix-servers as well. On their web-page it says: "Enhanced Operating System for High-Productivity Computing" [aka Linux] with "High-performance NUMA support".

Anyone ever seen a patch for this?

- jarman

Re:Isn't there some other numa stuff already in?

[Anonymous Coward]

Well, IBM has lots of scheduler experience. This is called processor affinity in the IBM world. Keep the process close to where its resources are.

And how does this relate to SGI?

[wfrp01]

SGI has also integrated NUMA technology into the linux kernel to support their new Altix servers. How do these two efforts relate? Is SGI's code generic enough that it could also be considered for inclusion in the mainstream kernel? Or is it specific to SGI's NUMA architecture? Is IBM's code generic enough that it would work on an Altix? What functional characteristics distinguish the two?