System uses numa Interleave mode as default policy?

System uses numa Interleave mode as default policy?

[Andreas Hollmann]

Hi,

it seems that my system (4-socket system) is
interleaving pages across all numa nodes.

The default should be local allocation?

I tried this out using the stream benchmark and pinned
the single thread to a single cpu with taskset.

numa_balancing is disabled.

Can I configure the default memory policy or is there
something wrong?

Configuration:

$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-linux
root=UUID=294db3db-d278-4b20-9199-f5ac6926efaf rw console=tty0
console=ttyS0,115200 numa_balancing=disable nomodeset quiet

$ uname -a
Linux inwest 3.12.6-1-ARCH #1 SMP PREEMPT Fri Dec 20 19:39:00 CET 2013
x86_64 GNU/Linux

Here is how i produced the output:

wget www.cs.virginia.edu/stream/FTP/Code/stream.c
gcc -mcmodel=medium -O -DSTREAM_ARRAY_SIZE=100000000 stream.c -o stream.100M

taskset -c 0 ./stream.100M 1> /dev/null & watch -n 1 numastat -cp $!

Per-node process memory usage (in MBs) for PID 2055 (stream.100M)
         Node 0 Node 1 Node 2 Node 3 Total
         ------ ------ ------ ------ -----
Huge          0      0      0      0     0
Heap        576    576    569    568  2289
Stack         0      0      0      0     0
Private       0      0      0      0     0
-------  ------ ------ ------ ------ -----
Total       576    576    569    568  2289

numactl -l taskset -c 0 ./stream.100M 1> /dev/null & watch -n 1 numastat -cp $!

Per-node process memory usage (in MBs) for PID 2333 (stream.100M)
         Node 0 Node 1 Node 2 Node 3 Total
         ------ ------ ------ ------ -----
Huge          0      0      0      0     0
Heap        576    573    568    572  2289
Stack         0      0      0      0     0
Private       0      0      0      0     0
-------  ------ ------ ------ ------ -----
Total       576    573    568    572  2289

numactl -m 0 taskset -c 0 ./stream.100M 1> /dev/null & watch -n 1
numastat -cp $!

Per-node process memory usage (in MBs) for PID 2394 (stream.100M)
         Node 0 Node 1 Node 2 Node 3 Total
         ------ ------ ------ ------ -----
Huge          0      0      0      0     0
Heap       2289      0      0      0  2289
Stack         0      0      0      0     0
Private       0      0      0      0     0
-------  ------ ------ ------ ------ -----
Total      2289      0      0      0  2289

---

$ numactl -s 0 taskset -c 0 ./stream.100M
policy: default
preferred node: current
physcpubind: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67
68 69 70 71 72 73 74 75 76 77 78 79
cpubind: 0 1 2 3
nodebind: 0 1 2 3
membind: 0 1 2 3

Thanks,
Andreas