Ubuntu Manpage: hwloc-bind - Launch a command that is bound to specific processors and/or memory, or consult the binding

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 [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.

OPTIONS

--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. The available policies are default, firsttouch, bind,
interleave replicate and nexttouch. 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.

--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.

-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.

--restrict <cpuset>
Restrict the topology to the given cpuset.

--whole-system
Do not consider administration limitations.

--hbm Only take high bandwidth memory nodes (such as KNL's MCDRAM) 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 hbm:1.

--no-hbm Ignore high bandwidth memory nodes (such as KNL's MCDRAM) when looking for NUMA nodes in the
input locations.

-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.

DESCRIPTION

       hwloc-bind  execs  an  executable  (with  optional command line arguments) that is bound to the specified
       location (or list of locations).  Upon successful execution, hwloc-bind simply  sets  bindings  and  then
       execs the executable over itself.

       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 memory on the first high-bandwidth memory node:

           $ hwloc-bind --membind hbm:0 -- echo hello
           $ hwloc-bind --membind --hbm 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

       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 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)

       Note that if the system is not NUMA, the reported string may indicate that the process is  bound  to  the
       entire system memory (e.g., "0xf...f").

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.