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HWLOC-DISTANCES(1) hwloc HWLOC-DISTANCES(1) NAME hwloc-distances - Displays distance matrices SYNOPSIS hwloc-distances [options] OPTIONS -l --logical Display hwloc logical indexes (default) instead of physical/OS in- dexes. -p --physical 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 in- put 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 gen- erally only available on Linux. The chroot was usually created by gathering another machine topology with hwloc-gather-topology. -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 topol- ogy 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 syn- thetic. --restrict <cpuset> Restrict the topology to the given cpuset. --whole-system Do not consider administration limitations. -v --verbose Verbose messages. --version Report version and exit. DESCRIPTION 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 la- tencies between NUMA nodes (which may or may not be accurate). See the de- finition of struct hwloc_distances_s in include/hwloc.h or the documenta- tion 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 per- formed starting from the root to find all distance matrices. NOTE: lstopo may also display distance matrices in its verbose textual out- put. However lstopo only prints matrices that cover the entire topology while hwloc-distances also displays matrices that ignore part of the topol- ogy. EXAMPLES On a quad-package opteron machine: $ hwloc-distances 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 RETURN VALUE 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. SEE ALSO hwloc(7), lstopo(1) 1.11.13 Jun 03, 2019 HWLOC-DISTANCES(1)
NAME | SYNOPSIS | OPTIONS | DESCRIPTION | EXAMPLES | RETURN VALUE | SEE ALSO
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