1 =============================== 1 ===============================
2 Numa policy hit/miss statistics 2 Numa policy hit/miss statistics
3 =============================== 3 ===============================
4 4
5 /sys/devices/system/node/node*/numastat 5 /sys/devices/system/node/node*/numastat
6 6
7 All units are pages. Hugepages have separate c 7 All units are pages. Hugepages have separate counters.
8 8
9 The numa_hit, numa_miss and numa_foreign count <<
10 are able to allocate memory from nodes they pr <<
11 is incremented on the preferred node, otherwis <<
12 the preferred node and numa_miss on the node w <<
13 <<
14 Usually preferred node is the one local to the <<
15 but restrictions such as mempolicies can chang <<
16 counters based on CPU local node. local_node i <<
17 incremented on allocation from a node by CPU o <<
18 similar to numa_miss and is incremented on the <<
19 from a CPU from a different node. Note there i <<
20 numa_foreign. <<
21 <<
22 In more detail: <<
23 <<
24 =============== ============================== 9 =============== ============================================================
25 numa_hit A process wanted to allocate m 10 numa_hit A process wanted to allocate memory from this node,
26 and succeeded. 11 and succeeded.
27 12
28 numa_miss A process wanted to allocate m 13 numa_miss A process wanted to allocate memory from another node,
29 but ended up with memory from 14 but ended up with memory from this node.
30 15
31 numa_foreign A process wanted to allocate o 16 numa_foreign A process wanted to allocate on this node,
32 but ended up with memory from !! 17 but ended up with memory from another one.
33 18
34 local_node A process ran on this node's C !! 19 local_node A process ran on this node and got memory from it.
35 and got memory from this node. <<
36 20
37 other_node A process ran on a different n !! 21 other_node A process ran on this node and got memory from another node.
38 and got memory from this node. <<
39 22
40 interleave_hit Interleaving wanted to allocat 23 interleave_hit Interleaving wanted to allocate from this node
41 and succeeded. 24 and succeeded.
42 =============== ============================== 25 =============== ============================================================
43 26
44 For easier reading you can use the numastat ut 27 For easier reading you can use the numastat utility from the numactl package
45 (http://oss.sgi.com/projects/libnuma/). Note t 28 (http://oss.sgi.com/projects/libnuma/). Note that it only works
46 well right now on machines with a small number 29 well right now on machines with a small number of CPUs.
47 30
48 Note that on systems with memoryless nodes (wh <<
49 memory) the numa_hit, numa_miss and numa_forei <<
50 heavily. In the current kernel implementation, <<
51 memoryless node (i.e. because it is running o <<
52 implementation actually treats one of the near <<
53 preferred node. As a result, such allocation w <<
54 counter on the memoryless node, and will skew <<
55 numa_foreign statistics of the nearest node. <<
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