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HWLOC-BIND(1)			     hwloc			 HWLOC-BIND(1)

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.

       --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.

       --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 (Intel Xeon Phi MCDRAM)
		 in  account  when  looking  for NUMA nodes in the input loca-
		 tions.

		 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 (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.  The	available policies are
		 default,  firsttouch,	bind,  interleave and nexttouch.  This
		 option	is only	meaningful when	 an  actual  binding  is  also
		 given	with  --membind.  If --membind is given	without	--mem-
		 policy, 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 EX-
		 AMPLES	below).

		 When a	command	is given, the binding is displayed before exe-
		 cuting	the command. When no command is	given, the program ex-
		 its after displaying the current binding.

		 When combined with --membind, report the memory  binding  in-
		 stead 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 node-
		 set=.

       -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 pro-
		 cessors at any	time according to the binding.

		 When a	command	is given, the last processors is displayed be-
		 fore  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	point-
		 ing  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).	 Loca-
       tion specification is described in hwloc(7).   Upon  successful	execu-
       tion,  hwloc-bind  simply  sets	bindings and then execs	the executable
       over itself.

       If a bitmask location is	given with prefix nodeset=, then it is consid-
       ered 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  exe-
       cutable.

       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  com-
       mand 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 high-bandwidth memory node  on  Intel  Xeon
       Phi:

	   $ hwloc-bind	--membind hbm: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  in-
       dex 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  sup-
       ported by the OS):

	   $ hwloc-bind	--cpubind node:1 --membind node:0 -- echo hello

       The --get option	can report current bindings.  This example shows nest-
       ing 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-read-
       able  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 re-
       trieve process bindings,	or lack	of a command to	execute.

SEE ALSO
       hwloc(7), lstopo(1), hwloc-calc(1), hwloc-distrib(1)

2.4.1				 Feb 11, 2021			 HWLOC-BIND(1)

NAME | SYNOPSIS | TOPOLOGY OPTIONS | OPTIONS | DESCRIPTION | EXAMPLES | HINT | RETURN VALUE | SEE ALSO

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