This is the command hwloc-distances that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
hwloc-distances - Displays distance matrices
Display hwloc logical indexes (default) instead of physical/OS indexes.
Display OS/physical indexes instead of hwloc logical indexes.
-i <file>, --input <file>
Read topology from XML file <file> (instead of discovering the topology on the
local machine). If <file> is "-", the standard input is used. XML support must
have been compiled in to hwloc for this option to be usable.
-i <directory>, --input <directory>
Read topology from the chroot specified by <directory> (instead of discovering the
topology on the local machine). This option is generally only available on Linux.
The chroot was usually created by gathering another machine topology with hwloc-
-i <specification>, --input <specification>
Simulate a fake hierarchy (instead of discovering the topology on the local
machine). If <specification> is "node:2 pu:3", the topology will contain two NUMA
nodes with 3 processing units in each of them. The <specification> string must end
with a number of PUs.
--if <format>, --input-format <format>
Enforce the input in the given format, among xml, fsroot and synthetic.
Restrict the topology to the given cpuset.
Do not consider administration limitations.
Report version and exit.
hwloc-distances displays also distance matrices attached to the topology. The value in
the i-th row and j-th column is the distance from object #i to object #j.
Unless defined by the user, matrices currently always contain relative latencies between
NUMA nodes (which may or may not be accurate). See the definition of struct
hwloc_distances_s in include/hwloc.h or the documentation for details.
These latencies are normalized to the latency of a local (non-NUMA) access. Hence 3.5 in
row #i column #j means that the latency from cores in NUMA node #i to memory in NUMA node
#j is 3.5 higher than the latency from cores to their local memory. A breadth-first
traversal of the topology is performed starting from the root to find all distance
NOTE: lstopo may also display distance matrices in its verbose textual output. However
lstopo only prints matrices that cover the entire topology while hwloc-distances also
displays matrices that ignore part of the topology.
On a quad-package opteron machine:
Latency matrix between 4 NUMANodes (depth 2) by logical indexes:
index 0 1 2 3
0 1.000 1.600 2.200 2.200
1 1.600 1.000 2.200 2.200
2 2.200 2.200 1.000 1.600
3 2.200 2.200 1.600 1.000
Upon successful execution, hwloc-distances returns 0.
hwloc-distances will return nonzero if any kind of error occurs, such as (but not limited
to) failure to parse the command line.
Use hwloc-distances online using onworks.net services