Re: hackbench regression due to commit 9dfc6e68bfe6e

From: Eric Dumazet
Date: Thu Apr 08 2010 - 01:39:26 EST



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


# cat try.sh
hackbench 50 process 5000
numactl --cpubind=0 --membind=0 hackbench 25 process 5000 >RES0 &
numactl --cpubind=1 --membind=1 hackbench 25 process 5000 >RES1 &
wait
echo node0 results
cat RES0
echo node1 results
cat RES1

numactl --cpubind=0 --membind=1 hackbench 25 process 5000 >RES0_1 &
numactl --cpubind=1 --membind=0 hackbench 25 process 5000 >RES1_0 &
wait
echo node0 on mem1 results
cat RES0_1
echo node1 on mem0 results
cat RES1_0

# ./try.sh
Running with 50*40 (== 2000) tasks.
Time: 16.865
node0 results
Running with 25*40 (== 1000) tasks.
Time: 16.767
node1 results
Running with 25*40 (== 1000) tasks.
Time: 16.564
node0 on mem1 results
Running with 25*40 (== 1000) tasks.
Time: 16.814
node1 on mem0 results
Running with 25*40 (== 1000) tasks.
Time: 16.896


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