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.

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.

-e --get-last-cpu-location
Report the last processors where the process ran. Note that the result may already be outdated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>

-p --physical
take OS/physical indexes instead of logical indexes

-l --logical
take logical indexes instead of physical/OS indexes (default)

--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.

-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 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

           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

       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

       On  one  of  the  hwloc  developer's  machines,  this  example reports "0x00004444,0x44000000".  The mask
       reported on your machine may be different.

       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

       Memory binding may also be reported:

           hwloc-bind --membind node:1 --mempolicy interleave -- hwloc-bind --get --membind

       This returns a string describing the memory binding, such as "0x000000f0 (interleave)".  Note that if the
       system does not contain any NUMA nodes, the reported string will 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.