HWLOC-CALC(1) hwloc HWLOC-CALC(1)
NAME
hwloc-calc - Operate on cpu mask strings and objects
SYNOPSIS
hwloc-calc [topology options] [options] <location1> [<location2> [...]
]
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.
TOPOLOGY OPTIONS
All topology options must be given before all other options.
--no-smt, --no-smt=<N>
Only keep the first PU per core in the input locations. If
<N> is specified, keep the <N>-th instead, if any. PUs are
ordered by physical index during this filtering.
--cpukind <n>
--cpukind <infoname>=<infovalue> Only keep PUs whose CPU kind
match. Either a single CPU kind is specified as an index, or
the info name/value keypair will select matching kinds.
When specified by index, it corresponds to hwloc ranking of
CPU kinds which returns energy-efficient cores first, and
high-performance power-hungry cores last. The full list of
CPU kinds may be seen with lstopo --cpukinds.
--restrict <cpuset>
Restrict the topology to the given cpuset.
--restrict nodeset=<nodeset>
Restrict the topology to the given nodeset, unless --re-
strict-flags specifies something different.
--restrict-flags <flags>
Enforce flags when restricting the topology. Flags may be
given as numeric values or as a comma-separated list of flag
names that are passed to hwloc_topology_restrict(). Those
names may be substrings of actual flag names as long as a
single one matches, for instance bynodeset,memless. The de-
fault is 0 (or none).
--disallowed
Include objects disallowed by administrative limitations.
-i <path>, --input <path>
Read the topology from <path> instead of discovering the
topology of the local machine.
If <path> is a file and XML support has been compiled in
hwloc, it may be a XML file exported by a previous hwloc pro-
gram. If <path> is "-", the standard input may be used as a
XML file.
On Linux, <path> may be a directory containing the topology
files gathered from another machine topology with hwloc-
gather-topology.
On x86, <path> may be a directory containing a cpuid dump
gathered with hwloc-gather-cpuid.
When the archivemount program is available, <path> may also
be a tarball containing such Linux or x86 topology files.
-i <specification>, --input <specification>
Simulate a fake hierarchy (instead of discovering the topol-
ogy on the local machine). If <specification> is "node:2
pu:3", the topology will contain two NUMA nodes with 3 pro-
cessing 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,
cpuid and synthetic.
OPTIONS
All these options must be given after all topology options above.
-p --physical
Use OS/physical indexes instead of logical indexes for both
input and output.
-l --logical
Use logical indexes instead of physical/OS indexes for both
input and output (default).
--pi --physical-input
Use OS/physical indexes instead of logical indexes for input.
--li --logical-input
Use logical indexes instead of physical/OS indexes for input
(default).
--po --physical-output
Use OS/physical indexes instead of logical indexes for out-
put.
--lo --logical-output
Use logical indexes instead of physical/OS indexes for output
(default, except for cpusets which are always physical).
-n --nodeset
Interpret both input and output sets as nodesets instead of
CPU sets. See --nodeset-output and --nodeset-input below for
details.
--no --nodeset-output
Report nodesets instead of CPU sets. This output is more
precise than the default CPU set output when memory locality
matters because it properly describes CPU-less NUMA nodes, as
well as NUMA-nodes that are local to multiple CPUs.
--ni --nodeset-input
Interpret input sets as nodesets instead of CPU sets.
-N --number-of <type|depth>
Report the number of objects of the given type or depth that
intersect the CPU set. This is convenient for finding how
many cores, NUMA nodes or PUs are available in a machine.
When combined with --nodeset or --nodeset-output, the nodeset
is considered instead of the CPU set for finding matching ob-
jects. This is useful when reporting the output as a number
or set of NUMA nodes.
If an OS device subtype such as gpu is given instead of os-
dev, only the os devices of that subtype will be counted.
-I --intersect <type|depth>
Find the list of objects of the given type or depth that in-
tersect the CPU set and report the comma-separated list of
their indexes instead of the cpu mask string. This may be
used for determining the list of objects above or below the
input objects.
When combined with --physical, the list is convenient to pass
to external tools such as taskset or numactl --physcpubind or
--membind. This is different from --largest since the latter
requires that all reported objects are strictly included in-
side the input objects.
When combined with --nodeset or --nodeset-output, the nodeset
is considered instead of the CPU set for finding matching ob-
jects. This is useful when reporting the output as a number
or set of NUMA nodes.
If an OS device subtype such as gpu is given instead of os-
dev, only the os devices of that subtype will be returned.
-H --hierarchical <type1>.<type2>...
Find the list of objects of type <type2> that intersect the
CPU set and report the space-separated list of their hierar-
chical indexes with respect to <type1>, <type2>, etc. For
instance, if package.core is given, the output would be Pack-
age:1.Core:2 Package:2.Core:3 if the input contains the third
core of the second package and the fourth core of the third
package.
Only normal CPU-side object types should be used.
NUMA nodes may be used but they may cause redundancy in the
output on heterogeneous memory platform. For instance, on a
platform with both DRAM and HBM memory on a package, the
first core will be considered both as first core of first
NUMA node (DRAM) and as first core of second NUMA node (HBM).
--largest Report (in a human readable format) the list of largest ob-
jects which exactly include all input objects (by looking at
their CPU sets). None of these output objects intersect each
other, and the sum of them is exactly equivalent to the in-
put. No largest object is included in the input This is dif-
ferent from --intersect where reported objects may not be
strictly included in the input.
--local-memory
Report the list of NUMA nodes that are local to the input ob-
jects.
This option is similar to -I numa but the way nodes are se-
lected is different: The selection performed by --local-mem-
ory may be precisely configured with --local-memory-flags,
while -I numa just selects all nodes that are somehow local
to any of the input objects.
--local-memory-flags
Change the flags used to select local NUMA nodes. Flags may
be given as numeric values or as a comma-separated list of
flag names that are passed to hwloc_get_local_numan-
ode_objs(). Those names may be substrings of actual flag
names as long as a single one matches. The default is 3 (or
smaller,larger) which means NUMA nodes are displayed if their
locality either contains or is contained in the locality of
the given object.
This option enables --local-memory.
--best-memattr <name>
Enable the listing of local memory nodes with --local-memory,
but only display the local node that has the best value for
the memory attribute given by <name> (or as an index).
If the memory attribute values depend on the initiator, the
hwloc-calc input objects are used as the initiator.
Standard attribute names are Capacity, Locality, Bandwidth,
and Latency. All existing attributes in the current topology
may be listed with
$ lstopo --memattrs
--sep <sep>
Change the field separator in the output. By default, a
space is used to separate output objects (for instance when
--hierarchical or --largest is given) while a comma is used
to separate indexes (for instance when --intersect is given).
--single Singlify the output to a single CPU.
--taskset Display CPU set strings in the format recognized by the
taskset command-line program instead of hwloc-specific CPU
set string format. This option has no impact on the format
of input CPU set strings, both formats are always accepted.
-q --quiet
Hide non-fatal error messages. It mostly includes locations
pointing to non-existing objects.
-v --verbose
Verbose output.
--version Report version and exit.
-h --help Display help message and exit.
DESCRIPTION
hwloc-calc generates and manipulates CPU mask strings or objects. Both
input and output may be either objects (with physical or logical in-
dexes), CPU lists (with physical or logical indexes), or CPU mask
strings (always physically indexed). Input location specification is
described in hwloc(7).
If objects or CPU mask strings are given on the command-line, they are
combined and a single output is printed. If no object or CPU mask
strings are given on the command-line, the program will read the stan-
dard input. It will combine multiple objects or CPU mask strings that
are given on the same line of the standard input line with spaces as
separators. Different input lines will be processed separately.
Command-line arguments and options are processed in order. First
topology configuration options should be given. Then, for instance,
changing the type of input indexes with --li or changing the input
topology with -i only affects the processing the following arguments.
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-calc utility.
EXAMPLES
hwloc-calc's operation is best described through several examples.
To display the (physical) CPU mask corresponding to the second package:
$ hwloc-calc package:1
0x000000f0
To display the (physical) CPU mask corresponding to the third pacakge,
excluding its even numbered logical processors:
$ hwloc-calc package:2 ~PU:even
0x00000c00
To convert a cpu mask to human-readable output, the -H option can be
used to emit a space-delimited list of locations:
$ echo 0x000000f0 | hwloc-calc -H package.core
Package:1.Core1 Package:1.Core:1 Package:1.Core:2 Package:1.Core:3
To use some other character (e.g., a comma) instead of spaces in out-
put, use the --sep option:
$ echo 0x000000f0 | hwloc-calc -H package.core --sep ,
Package:1.Core1,Package:1.Core:1,Package:1.Core:2,Package:1.Core:3
To combine two (physical) CPU masks:
$ hwloc-calc 0x0000ffff 0xff000000
0xff00ffff
To display the list of logical numbers of processors included in the
second package:
$ hwloc-calc --intersect PU package:1
4,5,6,7
To bind GNU OpenMP threads logically over the whole machine, we need to
use physical number output instead:
$ export GOMP_CPU_AFFINITY=`hwloc-calc --physical-output --inter-
sect PU all`
$ echo $GOMP_CPU_AFFINITY
0,4,1,5,2,6,3,7
To display the list of NUMA nodes, by physical indexes, that intersect
a given (physical) CPU mask:
$ hwloc-calc --physical --intersect NUMAnode 0xf0f0f0f0
0,2
To find how many cores are in the second CPU kind (those cores are
likely higher-performance and more power-hungry than cores of the first
kind):
$ hwloc-calc --cpukind 1 -N core all
4
To display the list of NUMA nodes, by physical indexes, whose locality
is exactly equal to a Package:
$ hwloc-calc --local-memory-flags 0 pack:1
4,7
To display the best-capacity NUMA node, by physical indexe, whose lo-
cality is exactly equal to a Package:
$ hwloc-calc --local-memory-flags 0 --best-memattr capacity pack:1
4
Converting object logical indexes (default) from/to physical/OS indexes
may be performed with --intersect combined with either --physical-out-
put (logical to physical conversion) or --physical-input (physical to
logical):
$ hwloc-calc --physical-output PU:2 --intersect PU
3
$ hwloc-calc --physical-input PU:3 --intersect PU
2
One should add --nodeset when converting indexes of memory objects to
make sure a single NUMA node index is returned on platforms with het-
erogeneous memory:
$ hwloc-calc --nodeset --physical-output node:2 --intersect node
3
$ hwloc-calc --nodeset --physical-input node:3 --intersect node
2
To display the set of CPUs near network interface eth0:
$ hwloc-calc os=eth0
0x00005555
To display the indexes of packages near PCI device whose bus ID is
0000:01:02.0:
$ hwloc-calc pci=0000:01:02.0 --intersect Package
1
To display the list of per-package cores that intersect the input:
$ hwloc-calc 0x00003c00 --hierarchical package.core
Package:2.Core:1 Package:3.Core:0
To display the (physical) CPU mask of the entire topology except the
third package:
$ hwloc-calc all ~package:3
0x0000f0ff
To combine both physical and logical indexes as input:
$ hwloc-calc PU:2 --physical-input PU:3
0x0000000c
To synthetize a set of cores into largest objects on a 2-node 2-package
2-core machine:
$ hwloc-calc core:0 --largest
Core:0
$ hwloc-calc core:0-1 --largest
Package:0
$ hwloc-calc core:4-7 --largest
NUMANode:1
$ hwloc-calc core:2-6 --largest
Package:1 Package:2 Core:6
$ hwloc-calc pack:2 --largest
Package:2
$ hwloc-calc package:2-3 --largest
NUMANode:1
To get the set of first threads of all cores:
$ hwloc-calc core:all.pu:0
$ hwloc-calc --no-smt all
This can also be very useful in order to make GNU OpenMP use exactly
one thread per core, and in logical core order:
$ export OMP_NUM_THREADS=`hwloc-calc --number-of core all`
$ echo $OMP_NUM_THREADS
4
$ export GOMP_CPU_AFFINITY=`hwloc-calc --physical-output --inter-
sect PU --no-smt all`
$ echo $GOMP_CPU_AFFINITY
0,2,1,3
To export bitmask in a format that is acceptable by the resctrl Linux
subsystem (for configuring cache partitioning, etc), apply a sed regexp
to the output of hwloc-calc:
$ hwloc-calc pack:all.core:7-9.pu:0
0x00000380,,0x00000380 <this format cannot be given to resctrl>
$ hwloc-calc pack:all.core:7-9.pu:0 | sed -e 's/0x//g' -e
's/,,/,0,/g' -e 's/,,/,0,/g'
00000380,0,00000380
# echo 00000380,0,00000380 > /sys/fs/resctrl/test/cpus
# cat /sys/fs/resctrl/test/cpus
00000000,00000380,00000000,00000380 <the modified bitmask was
corrected parsed by resctrl>
OS devices may also be filtered by subtype. In this example, there are
8 OS devices in the system, 4 of them are near NUMA node #1, and only 2
of these are CoProcessors:
$ utils/hwloc/hwloc-calc -I osdev all
0,1,2,3,4,5,6,7,8
$ utils/hwloc/hwloc-calc -I osdev node:1
5,6,7,8
$ utils/hwloc/hwloc-calc -I coproc node:1
7,8
RETURN VALUE
Upon successful execution, hwloc-calc displays the (physical) CPU mask
string, (physical or logical) object list, or (physical or logical) ob-
ject number list. The return value is 0.
hwloc-calc 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)
2.9.0 Dec 14, 2022 HWLOC-CALC(1)
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