Provided by: hwloc-nox_2.10.0-1build1_amd64 
NAME
hwloc-bind - Launch a command that is bound to specific processors and/or memory, or
consult the binding of an existing program
SYNOPSIS
hwloc-bind [topology options] [options] <location1> [<location2> [...] ] [--] <command>
...
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 before binding. If <N> is specified, keep the
<N>-th instead, if any. PUs are ordered by physical index during this
filtering.
Note that this option is applied after searching locations. Hence --no-smt
pu:2-5 will first select the PUs #2 to #5 in the machine before binding on one
of them per core. To rather bind on PUs #2 to #5 after filtering one per core,
you should combine with hwloc-calc:
hwloc-bind $(hwloc-calc --restrict $(hwloc-calc --no-smt all) pu:2-5) -- echo
hello
--restrict <cpuset>
Restrict the topology to the given cpuset. This removes some PUs and their now-
child-less parents.
Beware that restricting the PUs in a topology may change the logical indexes of
many objects, including NUMA nodes.
--restrict nodeset=<nodeset>
Restrict the topology to the given nodeset (unless --restrict-flags specifies
something different). This removes some NUMA nodes and their now-child-less
parents.
Beware that restricting the NUMA nodes in a topology may change the logical
indexes of many objects, including PUs.
--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 default is
0 (or none).
--disallowed
Include objects disallowed by administrative limitations.
--best-memattr <name>
Select the best NUMA node among the given memory binding set by looking at the
memory attribute given by <name> (or as an index).
If the memory attribute values depend on the initiator, the CPU binding set is
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
--hbm Only take high bandwidth memory nodes (marked with "HBM" subtype, or "MCDRAM" on
Intel Xeon Phi) in account when looking for NUMA nodes in the input locations.
This option must be combined with NUMA node locations, such as --hbm numa:1 for
binding on the second HBM node. It may also be written as numa[hbm]:1 or
numa[mcdram]:1.
--no-hbm Ignore high bandwidth memory nodes (marked with "HBM" subtype, or "MCDRAM" on
Intel Xeon Phi MCDRAM) when looking for NUMA nodes in the input locations.
OPTIONS
All these options must be given after all topology options above.
--cpubind Use following arguments for CPU binding (default).
--membind Use following arguments for memory binding. If --mempolicy is not also given,
the default policy is bind.
--mempolicy <policy>
Change the memory binding policy.
This option is only meaningful when an actual binding is also given with
--membind. If --membind is given without --mempolicy, the default policy is
bind.
The available policies are default, firsttouch, bind, interleave and nexttouch.
See hwloc.h for details about these policies.
Note that hwloc's memory binding policies may be slightly different from
operating system policies. For instance, the hwloc bind policy uses Linux
MPOL_PREFERRED_MANY (or MPOL_PREFERRED) by default, but it switches to Linux
MPOL_BIND if the hwloc strict option or flag is also given.
--get Report the current bindings. The output is an opaque bitmask that may be
translated into objects with hwloc-calc (see EXAMPLES below).
When a command is given, the binding is displayed before executing the command.
When no command is given, the program exits after displaying the current
binding.
When combined with --membind, report the memory binding instead of CPU binding.
No location may be given since no binding is performed.
--nodeset Report binding as a NUMA memory node set instead of a CPU set if --get was
given. This is useful for manipulating CPU-less NUMA nodes since their cpuset
is empty while their nodeset is correct.
Also parse input bitmasks as nodesets instead of cpusets.
When this option is not passed, individual input bitmasks may still be parsed as
nodesets if they are prefixed with nodeset=.
-e --get-last-cpu-location
Report the last processors where the process ran. The output is an opaque
bitmask that may be translated into objects with hwloc-calc (see EXAMPLES
below).
Note that the result may already be outdated when reported since the operating
system may move the process to other processors at any time according to the
binding.
When a command is given, the last processors is displayed before executing the
command. When no command is given, the program exits after displaying the last
processors.
This option cannot be combined with --membind.
No location may be given since no binding is performed.
--single Bind on a single CPU to prevent migration.
--strict Require strict binding.
--pid <pid>
Operate on pid <pid>
--tid <tid>
Operate on thread <tid> instead of on an entire process. The feature is only
supported on Linux for thread CPU binding, or for reporting the last processor
where the thread ran if -e was also passed.
-p --physical
Interpret input locations with OS/physical indexes instead of logical indexes.
This option does not apply to the output, see --get above.
-l --logical
Interpret input locations with logical indexes instead of physical/OS indexes
(default). This option does not apply to the output, see --get above.
--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.
-f --force
Launch the executable even if binding failed.
-q --quiet
Hide non-fatal error messages. It includes locations pointing to non-existing
objects, as well as failure to bind. This is usually useful in addition to
--force.
-v --verbose
Verbose output.
--version Report version and exit.
-h --help Display help message and exit.
DESCRIPTION
hwloc-bind execs an executable (with optional command line arguments) that is bound to the
specified location (or list of locations). Location specification is described in
hwloc(7). Upon successful execution, hwloc-bind simply sets bindings and then execs the
executable over itself.
If a bitmask location is given with prefix nodeset=, then it is considered a nodeset
instead of a CPU set. See also --nodeset.
If multiple locations are given, they are combined in the sense that the binding will be
wider. The process will be allowed to run on every location inside the combination.
The list of input locations may be explicitly ended with "--".
If binding fails, or if the binding set is empty, and --force was not given, hwloc-bind
returns with an error instead of launching the executable.
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-
bind utility.
EXAMPLES
hwloc-bind's operation is best described through several examples. More details about how
locations are specified on the hwloc-bind command line are described in hwloc(7).
To run the echo command on the first logical processor of the second package:
$ hwloc-bind package:1.pu:0 -- echo hello
which is exactly equivalent to the following line as long as there is no ambiguity between
hwloc-bind option names and the executed command name:
$ hwloc-bind package:1.pu:0 echo hello
To bind the "echo" command to the first core of the second package and the second core of
the first package:
$ hwloc-bind package:1.core:0 package:0.core:1 -- echo hello
To bind on the first PU of all cores of the first package:
$ hwloc-bind package:0.core:all.pu:0 -- echo hello
$ hwloc-bind --no-smt package:0 -- echo hello
To bind on the memory node local to a PU with largest capacity:
$ hwloc-bind --best-memattr capacity --cpubind pu:23 --membind pu:23 -- echo hello
To bind memory on the first NUMA node marked with "HBM" subtype:
$ hwloc-bind --membind numa[hbm]:0 -- echo hello
$ hwloc-bind --hbm --membind numa:0 -- echo hello
To bind memory on the first high-bandwidth memory node (MCDRAM) on Intel Xeon Phi:
$ hwloc-bind --membind numa[mcdram]:0 -- echo hello
$ hwloc-bind --hbm --membind numa:0 -- echo hello
Note that binding the "echo" command to multiple processors is probably meaningless
(because "echo" is likely implemented as a single-threaded application); these examples
just serve to show what hwloc-bind can do.
To run on the first three packages on the second and third nodes:
$ hwloc-bind node:1-2.package:0:3 -- echo hello
which is also equivalent to:
$ hwloc-bind node:1-2.package:0-2 -- echo hello
Note that if you attempt to bind to objects that do not exist, hwloc-bind will not warn
unless -v was specified.
To run on processor with physical index 2 in package with physical index 1:
$ hwloc-bind --physical package:1.core:2 -- echo hello
To run on odd cores within even packages:
$ hwloc-bind package:even.core:odd -- echo hello
To run on the first package, except on its second and fifth cores:
$ hwloc-bind package:0 ~package:0.core:1 ~package:0.core:4 -- echo hello
To run anywhere except on the first package:
$ hwloc-bind all ~package:0 -- echo hello
To run on a core near the network interface named eth0:
$ hwloc-bind os=eth0 -- echo hello
To run on a core near the PCI device whose bus ID is 0000:01:02.0:
$ hwloc-bind pci=0000:01:02.0 -- echo hello
To bind memory on second memory node and run on first node (when supported by the OS):
$ hwloc-bind --cpubind node:1 --membind node:0 -- echo hello
hwloc-bind does not have an option to select a kind of CPU core but it may be combined
with hwloc-calc to do so. For instance, to bind on the first two cores whose kind matches
CoreType=IntelAtom:
$ hwloc-bind $(hwloc-calc --restrict $(hwloc-calc --cpukind CoreType=IntelAtom all)
core:0-1) -- echo hello
The --get option can report current bindings. This example shows nesting hwloc-bind
invocations to set a binding and then report it:
$ hwloc-bind node:1.package:2 -- hwloc-bind --get
0x00004444,0x44000000
hwloc-calc can also be used to convert cpu mask strings to human-readable package/core/PU
strings; see the description of -H in hwloc-calc(1) for more details. The following
example binds to all the PUs in a specific core, uses the --get option to retrieve where
the process was actually bound, and then uses hwloc-calc to display the resulting cpu mask
in space-delimited list of human-readable locations:
$ hwloc-bind package:1.core:2 -- hwloc-bind --get | hwloc-calc -H package.core.pu
Package:1.Core:2.PU:0 Package:1.Core:2.PU:1
hwloc-calc may convert this output into actual objects, either with logical or physical
indexes:
$ hwloc-calc --physical -I pu `hwloc-bind --get`
26,30,34,38,42,46
$ hwloc-calc --logical -I pu `hwloc-bind --get` --sep " "
24 25 26 27 28 29
Locations may also be specified as a hex bit mask (typically generated by hwloc-calc).
For example:
$ hwloc-bind 0x00004444,0x44000000 -- echo hello
$ hwloc-bind `hwloc-calc node:1.package:2` -- echo hello
The current memory binding may also be reported:
$ hwloc-bind --membind node:1 --mempolicy interleave -- hwloc-bind --get --membind
0x000000f0 (interleave)
HINT
If the graphics-enabled lstopo is available, use for instance
$ hwloc-bind core:2 -- lstopo --pid 0
to check what the result of your binding command actually is. lstopo will graphically
show where it is bound to by hwloc-bind.
RETURN VALUE
Upon successful execution, hwloc-bind execs the command over itself. The return value is
therefore whatever the return value of the command is.
hwloc-bind will return nonzero if any kind of error occurs, such as (but not limited to):
failure to parse the command line, failure to retrieve process bindings, or lack of a
command to execute.
SEE ALSO
hwloc(7), lstopo(1), hwloc-calc(1), hwloc-distrib(1)