NUMACTL(8)                                        Linux Administrator's Manual                                        NUMACTL(8)



NAME
       numactl - Control NUMA policy for processes or shared memory

SYNOPSIS
       numactl  [ --interleave nodes ] [ --preferred node ] [ --membind nodes ] [ --cpunodebind nodes ] [ --physcpubind cpus ] [
       --localalloc ] [--] command {arguments ...}
       numactl --show
       numactl --hardware
       numactl [ --huge ] [ --offset offset ] [ --shmmode shmmode ] [ --length length ] [ --strict ]
       [ --shmid id ] --shm shmkeyfile | --file tmpfsfile
       [ --touch ] [ --dump ] [ --dump-nodes ] memory policy

DESCRIPTION
       numactl runs processes with a specific NUMA scheduling or memory placement policy.  The policy is  set  for  command  and
       inherited by all of its children.  In addition it can set persistent policy for shared memory segments or files.

       Use -- before command if using command options that could be confused
              with numactl options.

       Policy settings are:

       --interleave=nodes, -i nodes
              Set  a memory interleave policy. Memory will be allocated using round robin on nodes.  When memory cannot be allo-
              cated on the current interleave target fall back to other nodes.  Multiple nodes may be specified on --interleave,
              --membind  and  --cpunodebind.   You may specify "all", which means all nodes in the current cpuset.  nodes may be
              specified as N,N,N or  N-N or N,N-N or  N-N,N-N and so forth.  Relative nodes may be specifed as +N,N,N  or   +N-N
              or +N,N-N and so forth. The + indicates that the node numbers are relative to the process' set of allowed nodes in
              its current cpuset.  A !N-N notation indicates the inverse of N-N, in other words all nodes except N-N.   If  used
              with + notation, specify !+N-N.

       --membind=nodes, -m nodes
              Only  allocate  memory from nodes.  Allocation will fail when there is not enough memory available on these nodes.
              nodes may be specified as noted above.

       --cpunodebind=nodes, -N nodes
              Only execute command on the CPUs of nodes.  Note that nodes may consist of multiple CPUs.  nodes may be  specified
              as noted above.

       --physcpubind=cpus, -C cpus
              Only  execute  process  on  cpus.   This  accepts  physical  cpu  numbers  as  shown  in  the  processor fields of
              /proc/cpuinfo, or relative cpus as in relative to the current cpuset.  You may specify "all", which means all cpus
              in  the current cpuset.  Physical cpus may be specified as N,N,N or  N-N or N,N-N or  N-N,N-N and so forth.  Rela-
              tive cpus may be specifed as +N,N,N or  +N-N or +N,N-N and so forth. The + indicates that the cpu numbers are rel-
              ative to the process' set of allowed cpus in its current cpuset.  A !N-N notation indicates the inverse of N-N, in
              other words all cpus except N-N.  If used with + notation, specify !+N-N.

       --localalloc, -l
              Always allocate on the current node.

       --preferred=node
              Preferably allocate memory on node, but if memory cannot be allocated there fall back to other nodes.  This option
              takes only a single node number.  Relative notation may be used.

       --show, -s
              Show NUMA policy settings of the current process.

       --hardware, -H
              Show inventory of available nodes on the system.

       Numactl can set up policy for a SYSV shared memory segment or a file in shmfs/hugetlbfs.

       This  policy  is  persistent and will be used by all mappings from that shared memory. The order of options matters here.
       The specification must at least include either of --shm, --shmid, --file to specify the shared memory segment or file and
       a memory policy like described above ( --interleave, --localalloc, --prefered, --membind ).

       --huge
       When creating a SYSV shared memory segment use huge pages.  Only valid before --shmid or --shm

       --offset
       Specify  offset into the shared memory segment. Default 0.  Valid units are m (for MB), g (for GB), k (for KB), otherwise
       it specifies bytes.

       --strict
       Give an error when a page in the policied area in the shared memory segment already was faulted  in  with  a  conflicting
       policy. Default is to silently ignore this.

       --shmmode shmmode
       Only valid before --shmid or --shm When creating a shared memory segment set it to numeric mode shmmode.

       --length length
       Apply policy to length range in the shared memory segment or make the segment length long Default is to use the remaining
       length Required when a shared memory segment is created and specifies the length of the new segment then. Valid units are
       m (for MB), g (for GB), k (for KB), otherwise it specifies bytes.

       --shmid id
       Create or use an shared memory segment with numeric ID id

       --shm shmkeyfile
       Create or use an shared memory segment, with the ID generated using ftok(3) from shmkeyfile

       --file tmpfsfile
       Set policy for a file in tmpfs or hugetlbfs

       --touch
       Touch  pages  to  enforce policy early. Default is to not touch them, the policy is applied when an applications maps and
       accesses a page.

       --dump
       Dump policy in the specified range.

       --dump-nodes
       Dump all nodes of the specific range (very verbose!)

       Valid node specifiers

       all                 All nodes
       number              Node number
       number1{,number2}   Node number1 and Node number2
       number1-number2     Nodes from number1 to number2
       ! nodes             Invert selection of the following specification.

EXAMPLES
       numactl --physcpubind=+0-4,8-12 myapplic arguments Run myapplic on cpus 0-4 and 8-12 of the current cpuset.

       numactl --interleave=all bigdatabase arguments Run big database with its memory interleaved on all CPUs.

       numactl --cpubind=0 --membind=0,1 process Run process on node 0 with memory allocated on node 0 and 1.

       numactl --cpubind=0 --membind=0,1 -- process -l Run process as above, but with an option (-l) that would be confused with
       a numactl option.

       numactl --preferred=1 numactl --show Set preferred node 1 and show the resulting state.

       numactl  --interleave=all  --shmkeyfile  /tmp/shmkey  Interleave  all  of  the  sysv  shared  memory regiion specified by
       /tmp/shmkey over all nodes.

       numactl --offset=1G --length=1G --membind=1 --file /dev/shm/A  --touch  Bind  the  second  gigabyte  in  the  tmpfs  file
       /dev/shm/A to node 1.

       numactl --localalloc /dev/shm/file Reset the policy for the shared memory file file to the default localalloc policy.

NOTES
       Requires an NUMA policy aware kernel.

       Command is not executed using a shell. If you want to use shell metacharacters in the child use sh -c as wrapper.

       Setting policy for a hugetlbfs file does currently not work because it cannot be extended by truncate.

       Shared  memory  segments  larger  than  numactl's address space cannot be completely policied. This could be a problem on
       32bit architectures.  Changing it piece by piece may work.

       The old --cpubind which accepts node numbers, not cpu numbers, is deprecated and replaced with the new --cpunodebind  and
       --physcpubind options.


FILES
       /proc/cpuinfo for the listing of active CPUs. See proc(5) for details.

       /sys/devices/system/node/node*/numastat for NUMA memory hit statistics.


COPYRIGHT
       Copyright 2002,2004 Andi Kleen, SuSE Labs.  numactl and the demo programs are under the GNU General Public License, v.2


SEE ALSO
       set_mempolicy(2)  ,  get_mempolicy(2)  ,  mbind(2)  ,  sched_setaffinity(2)  , sched_getaffinity(2) , proc(5) , ftok(3) ,
       shmat(2) , migratepages(8)




SuSE Labs                                                   Mar 2004                                                  NUMACTL(8)