numad(8) Administration numad(8)numadnumad - A user-level daemon that provides placement advice and process
management for efficient use of CPUs and memory on systems with NUMA
topology.
SYNTAXnumad [-dhvV]
numad [-D non-standard-cgroup-mount-point]
numad [-i [min_interval:]max_interval]
numad [-K 0|1]
numad [-l log_level]
numad [-p PID]
numad [-r PID]
numad [-S 0|1]
numad [-u target_utilization]
numad [-w NCPUS[:MB]]
numad [-x PID]
DESCRIPTION
Numad is a system daemon that monitors NUMA topology and resource
usage. It will attempt to locate processes for efficient NUMA locality
and affinity, dynamically adjusting to changing system conditions.
Numad also provides guidance to assist management applications with
initial manual binding of CPU and memory resources for their processes.
Note that numad is primarily intended for server consolidation environ‐
ments, where there might be multiple applications or multiple virtual
guests running on the same server system. Numad is most likely to have
a positive effect when processes can be localized in a subset of the
system's NUMA nodes. If the entire system is dedicated to a large in-
memory database application, for example -- especially if memory
accesses will likely remain unpredictable --numad will probably not
improve performance.
OPTIONS-d Debug output in log, sets the log level to LOG_DEBUG. Same
effect as -l 7.
-D <non-standard-cgroup-mount-point>
This option can be used to communicate a non-standard cgroup
mount point to numad. This is not normally necessary.
-h Display usage help information and then exit.
-i <[min_interval:]max_interval>
Sets the time interval that numad waits between system scans, in
seconds to <max_interval>. Default <max_interval> is 15 seconds,
default <min_interval> is 5 seconds. Setting a <max_interval>
of zero will cause the daemon to exit. (This is the normal
mechanism to terminate the daemon.) A bigger <max_interval>
will decrease numad overhead but also decrease responsiveness to
changing loads.
-K <0|1>
This option controls whether numad keeps interleaved memory
spread across NUMA nodes, or attempts to merge interleaved mem‐
ory to local NUMA nodes. The default is to merge interleaved
memory. This is the appropriate setting to localize processes
in a subset of the system's NUMA nodes. If you are running a
large, single-instance application that allocates interleaved
memory because the workload will have continuous unpredictable
memory access patterns (e.g. a large in-memory database), you
might get better results by specifying -K 1 to instruct numad to
keep interleaved memory distributed.
-l <log_level>
Sets the log level to <log_level>. Reasonable choices are 5, 6,
or 7. The default value is 5.
-p <PID>
Add PID to explicit inclusion list of processes to consider for
managing, if the process also uses significant resources. Mul‐
tiple -p PID options can be specified at daemon start, but after
daemon start, only one PID can be added to the inclusion list
per subsequent numad invocation. Use with -S to precisely con‐
trol the scope of processes numad can manage. Note that the
specified process will not necessarily be actively managed
unless it also meets numad's significance threshold -- which is
currently 300MB and half of a CPU.
-r <PID>
Remove PID from both the explicit inclusion and the exclusion
lists of processes. After daemon start, only one PID can be
removed from the explicit process lists per subsequent numad
invocation. Use with -S and -p and -x to precisely control the
scope of processes numad can manage.
-S <0|1>
This option controls whether numad scans all system processes or
only the processes on the explicit inclusion PID list. The
default is to scan all processes. Use -S 0 to scan only the
explicit inclusion PID list. Use -S 1 to again scan all system
processes (excepting those on the explicit exclusion list).
Starting numad as
numad-S 0 -p <PID-1> -p <PID-2> -p <PID-3>
will limit scanning, and thus also automatic NUMA management, to
only those three explicitly specified processes.
-u <target_utilization>
Set the desired maximum consumption percentage of a node.
Default is 85%. Decrease the target value to maintain more
available resource margin on each node. Increase the target
value to more exhaustively consume node resources.
-v Verbose output in log, sets the log level to LOG_INFO. Same
effect as -l 6.
-V Display version information and exit.
-w <NCPUS[:MB]>
Queries numad for the best NUMA nodes to bind an entity that
needs <NCPUS>. The amount of memory (in MBs) is optional, but
should normally be specified as well <:MB> so numad can recom‐
mend NUMA nodes with available CPU capacity and adequate free
memory. This query option can be used regardless of whether
numad is running as a daemon. (An invocation using this option
when numad is not running as a daemon, will not cause the daemon
to start.) Output of this option is a string that contains a
NUMA node list. For example: 2-3,6. The recommended node list
could be saved in a shell variable (e.g., NODES) and then used
as the node list parameter in a
numactl -m $NODES -N $NODES ...
command. See numactl(8).
-x <PID>
Add PID to explicit exclusion list of processes to blacklist
from managing. Multiple -x PID options can be specified at dae‐
mon start, but after daemon start, only one PID can be added to
the exclusion list per subsequent numad invocation. Use with -S
to precisely control the scope of processes numad can manage.
FILES
/usr/bin/numad
/var/log/numad.log
/var/run/numad.pid
ENVIRONMENT VARIABLES
None.
EXAMPLES
Numad is normally run as a system daemon and should be managed by the
standard init mechanisms of the host.
If interactive (manual) control is desired, you can start the daemon
manually by typing:
/usr/bin/numad
Subsequent numad invocations while the daemon is running can be used to
dynamically change run-time options.
AUTHORS
Bill Gray <bgray@redhat.com>
SEE ALSOnumactl(8)Bill Gray 1.0.0 numad(8)
