hwloc-annotate - Man Page

Modify attributes in a XML topology


hwloc-annotate [options] <input.xml> <output.xml> -- <location1> <location2> ... -- <mode> <annotation>

hwloc-annotate [options] <input.xml> <output.xml> <location> <mode> <annotation>

Note that hwloc(7) provides a detailed explanation of the hwloc system and of valid <location> formats; it should be read before reading this man page.



Remove all info attributes that exist with the same name before adding the new one. This option is only accepted in "info" mode. If the info value is omitted, existing infos are replaced with nothing.


Clear the existing info attributes in the target objects before annotating. If no new annotation has to be added after clearing, mode should be set to none.


Clear the existing userdata from the target objects. If nothing else has to be performed after clearing, mode should be set to none.


Clear the existing distances from the topology. If nothing else has to be performed after clearing, mode should be set to none.

-h --help

Display help message and exit.


hwloc-annotate loads a topology from a XML file, adds some annotations, and export the resulting topology to another XML file. The input and output files may be the same.

The annotation may be string info attributes. This is specified by the mode:

info <name> <value>

Specifies a new string info attribute whose name is name and value is value.

misc <name>

Specifies a new Misc object name.

memattr <name> <flags>

Register a new memory attribute whose name is name and flags is flags. location is ignored in this mode.

Flags may be given as numeric values or as a comma-separated list of flag names that are passed to hwloc_memattr_register(). Those names may be substrings of actual flag names as long as a single one matches. For instance, a value of 1 (or higher) means that highest values are considered best for this attribute.

memattr <name> <initiator> <value>

Set the memory attribute (whose name is name) from initiator initiator (either an object or a CPU-set) to target NUMA node location to value value.

If this attribute does not require specific initiators, initiator is ignored.

Standard attribute names are Capacity, Locality, Bandwidth, and Latency. All existing attributes in the input topology may be listed with

   $ lstopo --memattrs -i input.xml

cpukind <cpuset> <efficiency> <flags> [<infoname> <infovalue>]

Specifies the kind of CPU for PUs listed in the given cpuset. location is ignored in this mode.

efficiency is an abstracted efficiency value that will enforce ranking of kinds. It should be -1 if unknown.

flags must be 0 for now.

If infoname and infovalue are given and non-empty, they are added as info attributes to this kind of CPU.

See the function hwloc_cpukinds_register() for details.

distances <filename> [<flags>]

Specifies new distances to be added to the topology using specifications in <filename>. The optional flags (0 unless specified) corresponds to the flags given to the function hwloc_distances_set(). location is ignored in this mode.

The first line of the pointed file must be a integer representing a distances kind as defined in hwloc/distances.h. The second line is the number of objects involved in the distances. The next lines contain one object each. The next lines contain one distance value each, or a single line may be given with a integer combination of format x*y or x*y*z.


No new annotation is added. This is useful when clearing existing attributes.

Annotations may be added to one specific object in the topology, all of them, or all of a given type. This is specified by the location (see also Examples below). Multiple locations may be affected if they are specified between --. Objects may be specified as location tuples, as explained in hwloc(7). However hexadecimal bitmasks are not accepted since they may correspond to multiple objects.

NOTE: The existing annotations may be listed with hwloc-info.

NOTE: It is highly recommended that you read the hwloc(7) overview page before reading this man page.  Most of the concepts described in hwloc(7) directly apply to the hwloc-annotate utility.


hwloc-annotate's operation is best described through several examples.

Add an info attribute to all Core and PU objects:

   $ hwloc-annotate input.xml output.xml -- Core:all PU:all -- info infoname infovalue

Only add to all Core objects:

   $ hwloc-annotate input.xml output.xml Core:all info infoname infovalue

Add a Misc object named "foobar" under the root object of the topology and modify the input XML directly:

   $ hwloc-annotate file.xml file.xml root misc foobar

Add an info attribute to OS device #2 and #3:

   $ hwloc-annotate input.xml output.xml os:2-3 info infoname infovalue

Change package objects to green with red text in the lstopo graphical output:

   $ hwloc-annotate topo.xml topo.xml package:all info lstopoStyle "Background=#00ff00;Text=#ff0000"
   $ lstopo -i topo.xml

Set the memory attribute latency to 123 nanoseconds from the PUs in the first package to the first NUMA node:

   $ hwloc-annotate topo.xml topo.xml numanode:0 memattr Latency $(hwloc-calc package:0) 123

Register a memory attribute MyApplicationPerformance (with flags specifying that it requires an initiator and reports higher values first) and set its value for initiator CPU-set 0x11 to NUMA node #2 to 2345:

   $ hwloc-annotate topo.xml topo.xml ignored memattr MyApplicationPerformance need_init,higher
   $ hwloc-annotate topo.xml topo.xml numanode:2 memattr MyApplicationPerformance 0x11 2345

Specify that PU 0-3 and PU 4-7 are of different kinds, and the latter is more efficient:

   $ hwloc-annotate topo.xml topo.xml dummy cpukind 0x0f 0 0 CoreType Small
   $ hwloc-annotate topo.xml topo.xml dummy cpukind 0xf0 1 0 CoreType Big

Return Value

Upon successful execution, hwloc-annotate generates the output topology. The return value is 0.

hwloc-annotate 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), hwloc-info(1)

Referenced By


Feb 11, 2021 2.4.1 hwloc