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
       ] [ --cpubind nodes ] [ --localalloc ] command {arguments ...}
       numactl --show
       numactl --hardware
       numactl [ --huge ] [ --offset offset ] [ --mode shmmode ]  [  --length
       length ] [ --strict ]
       --shmid id | --shm shmkeyfile | --file tmpfsfile
       [ --touch ] [ --dump ] 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.

       Policy settings are:

       --interleave=nodes, -i nodes
	      Set an memory interleave policy. Memory will be allocated using
	      round  robin  on nodes.  When memory cannot be allocated on the
	      current interleave target fall back to other nodes.

       --membind=nodes, -m nodes
	      Only allocate memory from nodes.	 Allocation  will  fail	 when
	      there is not enough memory available on these nodes.

       --cpubind=nodes, -c nodes
	      Only execute process on the CPUs of nodes.

       --localalloc, -l
	      Do always local allocation 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.

       --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.

       --mode shmmode
       Only valid before --shmid or --shm When creating a shared memory	 seg-
       ment 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.

       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	--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 --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.


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

       /sys/devices/system/node/node*/numastat	for  NUMA  memory hit statis-
       tics.


COPYRIGHT
       Copyright 2002,2004 Andi Kleen, SuSE Labs.  numactl and the demo	 pro-
       grams 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)



SuSE Labs			   Mar 2004			   NUMACTL(8)

UNIX/Linux commands referenced on this page:

1. id
2. at
3. file
4. make
5. touch
6. sh
7. as