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CPUSET(1)		  BSD General Commands Manual		     CPUSET(1)

     cpuset -- configure processor sets

     cpuset [-l	cpu-list] [-s setid] cmd
     cpuset [-l	cpu-list] [-s setid] -p	pid
     cpuset [-cr] [-l cpu-list]	[-p pid	| -r tid | -s setid]
     cpuset [-cgir] [-p	pid | -r tid | -s setid]

     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 in-
     formation about processor binding,	sets, and available processors in the

     cpuset requires a target to modify	or query.  The target may be specified
     as	a command, process id, thread id, or a cpuset id.  Using -g the	tar-
     get'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.

     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.

     -l	cpu-list  Specifies a list of CPUs to apply to a target.  Specifica-
		  tion may include numbers seperated 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.

     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 <>

BSD				 March 2, 2008				   BSD


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