Re: hackbench regression due to commit 9dfc6e68bfe6e

From: Eric Dumazet
Date: Thu Apr 08 2010 - 11:52:32 EST


Le jeudi 08 avril 2010 Ã 10:34 -0500, Christoph Lameter a Ãcrit :
> On Thu, 8 Apr 2010, Eric Dumazet wrote:
>
> > I suspect NUMA is completely out of order on current kernel, or my
> > Nehalem machine NUMA support is a joke
> >
> > # numactl --hardware
> > available: 2 nodes (0-1)
> > node 0 size: 3071 MB
> > node 0 free: 2637 MB
> > node 1 size: 3062 MB
> > node 1 free: 2909 MB
>
> How do the cpus map to the nodes? cpu 0 and 1 both on the same node?

one socket maps to 0 2 4 6 8 10 12 14 (Node 0)
one socket maps to 1 3 5 7 9 11 13 15 (Node 1)

# numactl --cpubind=0 --membind=0 numactl --show
policy: bind
preferred node: 0
interleavemask:
interleavenode: 0
nodebind: 0
membind: 0
cpubind: 1 3 5 7 9 11 13 15 1024

(strange 1024 report...)

# numactl --cpubind=1 --membind=1 numactl --show
policy: bind
preferred node: 1
interleavemask:
interleavenode: 0
nodebind:
membind: 1
cpubind: 0 2 4 6 8 10 12 14



[ 0.161170] Booting Node 0, Processors #1
[ 0.248995] CPU 1 MCA banks CMCI:2 CMCI:3 CMCI:5 CMCI:6 SHD:8
[ 0.269177] Ok.
[ 0.269453] Booting Node 1, Processors #2
[ 0.356965] CPU 2 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.377207] Ok.
[ 0.377485] Booting Node 0, Processors #3
[ 0.464935] CPU 3 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.485065] Ok.
[ 0.485217] Booting Node 1, Processors #4
[ 0.572906] CPU 4 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.593044] Ok.
...
grep "physical id" /proc/cpuinfo
physical id : 1
physical id : 0
physical id : 1
physical id : 0
physical id : 1
physical id : 0
physical id : 1
physical id : 0
physical id : 1
physical id : 0
physical id : 1
physical id : 0
physical id : 1
physical id : 0
physical id : 1
physical id : 0


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