CPUSET(1) FreeBSD General Commands Manual CPUSET(1)
NAME
cpuset - configure processor sets
SYNOPSIS
cpuset [-l cpu-list] [-n policy:domain-list] [-s setid] cmd ...
cpuset [-l cpu-list] [-n policy:domain-list] [-s setid] -p pid
cpuset [-c] [-l cpu-list] [-n policy:domain-list] -C -p pid
cpuset [-c] [-l cpu-list] [-n policy:domain-list]
[-j jail | -p pid | -t tid | -s setid | -x irq]
cpuset -g [-cir]
[-d domain | -j jail | -p pid | -t tid | -s setid | -x irq]
DESCRIPTION
The cpuset command can be used to assign processor sets to processes, run
commands constrained to a given set or list of processors and memory
domains, and query information about processor binding, memory binding
and policy, sets, and available processors and memory domains in the
system.
cpuset requires a target to modify or query. The target may be specified
as a command, process id, thread id, a cpuset id, an irq, a jail, or a
NUMA domain. Using -g the target's set id or mask may be queried. Using
-l or -s the target's CPU mask or set id may be set. If no target is
specified, cpuset operates on itself. Not all combinations of operations
and targets are supported. For example, you may not set the id of an
existing set or query and launch a command at the same time.
There are two sets applicable to each process and one private mask per
thread. Every process in the system belongs to a cpuset. By default
processes are started in set 1. The mask or id may be queried using -c.
Each thread also has a private mask of CPUs it is allowed to run on that
must be a subset of the assigned set. And finally, there is a root set,
numbered 0, that is immutable. This last set is the list of all possible
CPUs in the system and is queried using -r.
Most sets include NUMA memory domain and policy information. This can be
inspected with -g and set with -n. This will specify which NUMA domains
are visible to the process and affect where anonymous memory and file
pages will be stored on first access. Files accessed first by other
processes may specify conflicting policy.
When running a command it may join a set specified with -s otherwise a
new set is created. In addition, a mask for the command may be specified
using -l. When used in conjunction with -c the mask modifies the
supplied or created set rather than the private mask for the thread.
The options are as follows:
-C Create a new cpuset and assign the target process to that
set.
-c The requested operation should reference the cpuset
available via the target specifier.
-d domain Specifies a NUMA domain id as the target of the operation.
This can only be used to query the cpus visible in each
numberd domain.
-g Causes cpuset to print either a list of valid CPUs or,
using -i, the id of the target.
-i When used with the -g option print the id rather than the
valid mask of the target.
-j jail Specifies a jail id or name as the target of the
operation.
-l cpu-list Specifies a list of CPUs to apply to a target.
Specification may include numbers separated by '-' for
ranges and commas separating individual numbers. A
special list of "all" may be specified in which case the
list includes all CPUs from the root set.
-n policy:domain-list
Specifies a list of domains and allocation policy to apply
to a target. Ranges may be specified as in -l. Valid
policies include first-touch (ft), round-robin (rr),
prefer and interleave (il). First-touch allocates on the
local domain when memory is available. Round-robin
alternates between every possible domain page at a time.
The prefer policy accepts only a single domain in the set.
The parent of the set is consulted if the preferred domain
is unavailable. Interleave operates like round-robin with
an implementation defined stripe width. See domainset(9)
for more details on policies.
-p pid Specifies a pid as the target of the operation.
-s setid Specifies a set id as the target of the operation.
-r The requested operation should reference the root set
available via the target specifier.
-t tid Specifies a thread id as the target of the operation.
-x irq Specifies an irq as the target of the operation.
EXIT STATUS
The cpuset utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
Create a new group with CPUs 0-4 inclusive and run /bin/sh on it:
cpuset -c -l 0-4 /bin/sh
Query the mask of CPUs the <sh pid> is allowed to run on:
cpuset -g -p <sh pid>
Restrict /bin/sh to run on CPUs 0 and 2 while its group is still allowed
to run on CPUs 0-4:
cpuset -l 0,2 -p <sh pid>
Modify the cpuset /bin/sh belongs to restricting it to CPUs 0 and 2:
cpuset -l 0,2 -c -p <sh pid>
Modify the cpuset all threads are in by default to contain only the first
4 CPUs, leaving the rest idle:
cpuset -l 0-3 -s 1
Print the id of the cpuset /bin/sh is in:
cpuset -g -i -p <sh pid>
Move the pid into the specified cpuset setid so it may be managed with
other pids in that set:
cpuset -s <setid> -p <pid>
Create a new cpuset that is restricted to CPUs 0 and 2 and move pid into
the new set:
cpuset -C -c -l 0,2 -p <pid>
SEE ALSO
nproc(1), cpuset(2), rctl(8)
HISTORY
The cpuset command first appeared in FreeBSD 7.1.
AUTHORS
Jeffrey Roberson <jeff@FreeBSD.org>
FreeBSD 15.1-STABLE-HBSD July 3, 2018 CPUSET(1)