CPUSET(1) BSD General Commands Manual CPUSET(1)NAMEcpuset — configure processor sets
SYNOPSIScpuset [-l cpu-list] [-s setid] cmd ...
cpuset [-l cpu-list] [-s setid] -p pid
cpuset [-cr] [-l cpu-list]
[-j jailid | -p pid | -t tid | -s setid | -x irq]
cpuset [-cgir] [-j jailid | -p pid | -t tid | -s setid | -x irq]
The cpuset command can be used to assign processor sets to processes, run
commands constrained to a given set or list of processors, and query
information about processor binding, sets, and available processors in
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 or a jail id.
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 tar‐
gets 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.
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 sup‐
plied or created set rather than the private mask for the thread.
The options are as follows:
-c The requested operation should reference the cpuset avail‐
able via the target specifier.
-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 jailid Specifies a jail id as the target of the operation.
-l cpu-list Specifies a list of CPUs to apply to a target. Specifica‐
tion may include numbers separated by '-' for ranges and
commas separating individual numbers.
-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 avail‐
able 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.
The cpuset utility exits 0 on success, and >0 if an error occurs.
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>
The cpuset command first appeared in FreeBSD 7.1.
Jeffrey Roberson ⟨jeff@FreeBSD.org⟩
BSD November 29, 2008 BSD