[PATCH] Linux NUMA support for HotSpot

Andi Kleen andi at firstfloor.org
Mon Mar 3 03:30:17 PST 2008

On Mon, Mar 03, 2008 at 12:52:40PM +0300, Igor Veresov wrote:
> I haven't studied your changes in detail but I have a NUMA-aware allocator for 
> Linux in works 

Ok maybe you can do something with my patch then.

> and I do see speedups, which are similar to what I was able to 
> get from Solaris. About 8% for specjbb2005 on a dual-socket Opteron. So it's 

Ok I only did micro benchmarks. Maybe they were not strong enough.
For some simple allocations I didn't get any numa local placement 
at least according to the benchmark numbers.

> all working quite well, actually.

One obvious issue I found in the Solaris code was that it neither
binds threads to nodes (afaik), nor tries to keep up with a thread migrating
to another node. It just assumes always the same thread:node mapping
which surely cannot be correct?

On the Linux implementation I solved that by using getcpu() on
each allocation (on recent Linux it is a special optimized fast path
that is quite fast) 

But I think there were some other issues too.


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