mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
55 lines
2.4 KiB
55 lines
2.4 KiB
=============================== |
|
Numa policy hit/miss statistics |
|
=============================== |
|
|
|
/sys/devices/system/node/node*/numastat |
|
|
|
All units are pages. Hugepages have separate counters. |
|
|
|
The numa_hit, numa_miss and numa_foreign counters reflect how well processes |
|
are able to allocate memory from nodes they prefer. If they succeed, numa_hit |
|
is incremented on the preferred node, otherwise numa_foreign is incremented on |
|
the preferred node and numa_miss on the node where allocation succeeded. |
|
|
|
Usually preferred node is the one local to the CPU where the process executes, |
|
but restrictions such as mempolicies can change that, so there are also two |
|
counters based on CPU local node. local_node is similar to numa_hit and is |
|
incremented on allocation from a node by CPU on the same node. other_node is |
|
similar to numa_miss and is incremented on the node where allocation succeeds |
|
from a CPU from a different node. Note there is no counter analogical to |
|
numa_foreign. |
|
|
|
In more detail: |
|
|
|
=============== ============================================================ |
|
numa_hit A process wanted to allocate memory from this node, |
|
and succeeded. |
|
|
|
numa_miss A process wanted to allocate memory from another node, |
|
but ended up with memory from this node. |
|
|
|
numa_foreign A process wanted to allocate on this node, |
|
but ended up with memory from another node. |
|
|
|
local_node A process ran on this node's CPU, |
|
and got memory from this node. |
|
|
|
other_node A process ran on a different node's CPU |
|
and got memory from this node. |
|
|
|
interleave_hit Interleaving wanted to allocate from this node |
|
and succeeded. |
|
=============== ============================================================ |
|
|
|
For easier reading you can use the numastat utility from the numactl package |
|
(http://oss.sgi.com/projects/libnuma/). Note that it only works |
|
well right now on machines with a small number of CPUs. |
|
|
|
Note that on systems with memoryless nodes (where a node has CPUs but no |
|
memory) the numa_hit, numa_miss and numa_foreign statistics can be skewed |
|
heavily. In the current kernel implementation, if a process prefers a |
|
memoryless node (i.e. because it is running on one of its local CPU), the |
|
implementation actually treats one of the nearest nodes with memory as the |
|
preferred node. As a result, such allocation will not increase the numa_foreign |
|
counter on the memoryless node, and will skew the numa_hit, numa_miss and |
|
numa_foreign statistics of the nearest node.
|
|
|