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NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | NOTES | FILES | COPYRIGHT | SEE ALSO | COLOPHON |
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NUMACTL(8) Linux Administrator's Manual NUMACTL(8)
numactl - Control NUMA policy for processes or shared memory
numactl [ --all ] [ --balancing ] [ --interleave nodes ] [
--weighted-interleave nodes ] [ --preferred node ] [ --preferred-
many nodes ] [ --membind nodes ] [ --cpunodebind nodes ] [
--physcpubind cpus ] [ --localalloc ] [--] command {arguments
...}
numactl --show
numactl --hardware [--cpu-compress]
numactl --version
numactl [ --huge ] [ --offset offset ] [ --shmmode shmmode ] [
--length length ] [ --strict ]
[ --shmid id ] --shm shmkeyfile | --file tmpfsfile
[ --touch ] [ --dump ] [ --dump-nodes ] memory policy
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.
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 specified 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. When same is specified the previous nodemask specified on
the command line is used. all means all nodes in the current
cpuset.
Instead of a number a node can also be:
netdev:DEV The node connected to network device DEV.
file:PATH The node the block device of PATH.
ip:HOST The node of the network device of HOST
block:PATH The node of block device PATH
pci:[seg:]bus:dev[:func] The node of a PCI device.
Note that block resolves the kernel block device names only for
udev names in /dev use file:
Policy settings are:
--all, -a
Unset default cpuset awareness, so user can use all
possible CPUs/nodes for following policy settings.
--interleave=nodes, -i nodes
Set a 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. Multiple nodes may be specified on
--interleave, --membind and --cpunodebind.
--weighted-interleave=nodes, -w nodes
Set a weighted memory interleave policy. Memory will be
allocated using the weighted ratio for each node, which
can be read from
/sys/kernel/mm/mempolicy/weighted_interleave/node*. 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.
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 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. Relative cpus may be
specified as +N,N,N or +N-N or +N,N-N and so forth. The +
indicates that the cpu numbers are relative 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
Try to allocate on the current node of the process, but if
memory cannot be allocated there fall back to other nodes.
--preferred=node, -p 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.
--balancing, -b
Enable Linux kernel NUMA balancing for the process if it
is supported by kernel. This should only be used with
--membind, -m only, otherwise ignored.
--preferred-many=nodes, -P nodes
Preferably allocate memory on nodes, but if memory cannot
be allocated there fall back to other nodes. This option
takes a mask of preferred nodes where the closest node to
local is considered most preferred. 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. When the
--cpu-compress option is set show cpu ranges. This is not
default not break any existing scripts.
Numactl can set up policy for a SYSV shared memory segment or a
file in shmfs/hugetlbfs.
--version
print the version of the numactl package and exit.
The following policy settings are 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, --preferred, --preferred-many, --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 a shared memory segment with numeric ID id
--shm shmkeyfile
Create or use a 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.
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 --weighted-interleave=all bigdatabase arguments Run big
database with its memory interleaved with weighted ratio on all
CPUs.
numactl --cpunodebind=0 --membind=0,1 process Run process on node
0 with memory allocated on node 0 and 1.
numactl --cpunodebind=0 --membind=0,1 -- process -l Run process
as above, but with an option (-l) that would be confused with a
numactl option.
numactl --cpunodebind=0 --balancing --membind=0,1 process Run
process on node 0 with memory allocated on node 0 and 1.
Optimize the page placement with Linux kernel NUMA balancing
mechanism if possible.
numactl --cpunodebind=netdev:eth0 --membind=netdev:eth0 network-
server Run network-server on the node of network device eth0 with
its memory also in the same node.
numactl --preferred=1 numactl --show Set preferred node 1 and
show the resulting state.
numactl --preferred-many=0x3 numactl --show Set preferred nodes 1
and 2, and show the resulting state.
numactl --length 1g --shm /tmp/shmkey --interleave=all Interleave
all of the sysv shared memory region of size 1g specified by
/tmp/shmkey over all nodes.
Place a tmpfs file on 2 nodes:
numactl --membind=2 dd if=/dev/zero of=/dev/shm/A bs=1M
count=1024
numactl --membind=3 dd if=/dev/zero of=/dev/shm/A seek=1024
bs=1M count=1024
numactl --localalloc /dev/shm/file Reset the policy for the
shared memory file file to the default localalloc policy.
Requires a 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.
/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 2002,2004 Andi Kleen, SuSE Labs. numactl and the demo
programs are under the GNU General Public License, v.2
set_mempolicy(2) , get_mempolicy(2) , mbind(2) ,
sched_setaffinity(2) , sched_getaffinity(2) , proc(5) , ftok(3) ,
shmat(2) , migratepages(8)
This page is part of the numactl (NUMA commands) project.
Information about the project can be found at
⟨http://oss.sgi.com/projects/libnuma/⟩. If you have a bug report
for this manual page, send it to [email protected].
This page was obtained from the project's upstream Git repository
⟨https://github.com/numactl/numactl.git⟩ on 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-10.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
SuSE Labs Mar 2004 NUMACTL(8)
Pages that refer to this page: get_mempolicy(2), mbind(2), sched_setaffinity(2), set_mempolicy(2), numa(3), cpuset(7), numa(7), migratepages(8), migspeed(8), numastat(8)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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