configure processor sets
-d domain |
-j jail |
-p pid |
-t tid |
-s setid |
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
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
-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
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
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
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:
- Create a new cpuset and assign the target process to that set.
- The requested operation should reference the cpuset available via the
- 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.
cpuset to print either a list of valid CPUs
-i, the id of the target.
- When used with the
-g option print the id rather
than the valid mask of the target.
- Specifies a jail id or name as the target of the operation.
- 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.
- 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
for more details on policies.
- Specifies a pid as the target of the operation.
- Specifies a set id as the target of the operation.
- The requested operation should reference the root set available via the
- Specifies a thread id as the target of the operation.
- Specifies an irq as the target of the operation.
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
cpuset -g -p <sh
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
Modify the cpuset /bin/sh belongs to
restricting it to CPUs 0 and 2:
cpuset -l 0,2 -c -p <sh
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
cpuset -g -i -p <sh
Move the pid into the specified cpuset
setid so it may be managed with other pids in that
cpuset -s <setid> -p
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
cpuset command first appeared in