228 lines
6.4 KiB
Groff
228 lines
6.4 KiB
Groff
.\" Copyright (c) 2008 Christian Brueffer
|
|
.\" Copyright (c) 2008 Jeffrey Roberson
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 8, 2010
|
|
.Dt CPUSET 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm cpuset ,
|
|
.Nm cpuset_getid ,
|
|
.Nm cpuset_setid
|
|
.Nd manage CPU affinity sets
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In sys/cpuset.h
|
|
.Ft int
|
|
.Fn cpuset "cpusetid_t *setid"
|
|
.Ft int
|
|
.Fn cpuset_setid "cpuwhich_t which" "id_t id" "cpusetid_t setid"
|
|
.Ft int
|
|
.Fn cpuset_getid "cpulevel_t level" "cpuwhich_t which" "id_t id" "cpusetid_t *setid"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
family of system calls allow applications to control sets of processors and
|
|
assign processes and threads to these sets.
|
|
Processor sets contain lists of CPUs that members may run on and exist only
|
|
as long as some process is a member of the set.
|
|
All processes in the system have an assigned set.
|
|
The default set for all processes in the system is the set numbered 1.
|
|
Threads belong to the same set as the process which contains them,
|
|
however, they may further restrict their set with the anonymous
|
|
per-thread mask.
|
|
.Pp
|
|
Sets are referenced by a number of type
|
|
.Ft cpuset_id_t .
|
|
Each thread has a root set, an assigned set, and an anonymous mask.
|
|
Only the root and assigned sets are numbered.
|
|
The root set is the set of all CPUs available in the system or in the
|
|
system partition the thread is running in.
|
|
The assigned set is a subset of the root set and is administratively
|
|
assignable on a per-process basis.
|
|
Many processes and threads may be members of a numbered set.
|
|
.Pp
|
|
The anonymous set is a further thread-specific refinement on the assigned
|
|
set.
|
|
It is intended that administrators will manipulate numbered sets using
|
|
.Xr cpuset 1
|
|
while application developers will manipulate anonymous sets using
|
|
.Xr cpuset_setaffinity 2 .
|
|
.Pp
|
|
To select the correct set a value of type
|
|
.Ft cpulevel_t
|
|
is used.
|
|
The following values for
|
|
.Fa level
|
|
are supported:
|
|
.Bl -column CPU_LEVEL_CPUSET -offset indent
|
|
.It Dv CPU_LEVEL_ROOT Ta "Root set"
|
|
.It Dv CPU_LEVEL_CPUSET Ta "Assigned set"
|
|
.It Dv CPU_LEVEL_WHICH Ta "Set specified by which argument"
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fa which
|
|
argument determines how the value of
|
|
.Fa id
|
|
is interpreted and is of type
|
|
.Ft cpuwhich_t .
|
|
The
|
|
.Fa which
|
|
argument may have the following values:
|
|
.Bl -column CPU_WHICH_CPUSET -offset indent
|
|
.It Dv CPU_WHICH_TID Ta "id is lwpid_t (thread id)"
|
|
.It Dv CPU_WHICH_PID Ta "id is pid_t (process id)"
|
|
.It Dv CPU_WHICH_CPUSET Ta "id is a cpusetid_t (cpuset id)"
|
|
.It Dv CPU_WHICH_IRQ Ta "id is an irq number"
|
|
.El
|
|
.Pp
|
|
An
|
|
.Fa id
|
|
of '-1' may be used with a
|
|
.Fa which
|
|
of
|
|
.Dv CPU_WHICH_TID ,
|
|
.Dv CPU_WHICH_PID ,
|
|
or
|
|
.Dv CPU_WHICH_CPUSET
|
|
to mean the current thread, process, or current thread's
|
|
cpuset.
|
|
All cpuset syscalls allow this usage.
|
|
.Pp
|
|
A
|
|
.Fa level
|
|
argument of
|
|
.Dv CPU_LEVEL_WHICH
|
|
combined with a
|
|
.Fa which
|
|
argument other than
|
|
.Dv CPU_WHICH_CPUSET
|
|
refers to the anonymous mask of the object.
|
|
This mask does not have an id and may only be manipulated with
|
|
.Xr cpuset_setaffinity 2 .
|
|
.Pp
|
|
.Fn cpuset
|
|
creates a new set containing the same CPUs as the root set of the current
|
|
process and stores its id in the space provided by
|
|
.Fa setid .
|
|
On successful completion the calling process joins the set and is the
|
|
only member.
|
|
Children inherit this set after a call to
|
|
.Xr fork 2 .
|
|
.Pp
|
|
.Fn cpuset_setid
|
|
attempts to set the id of the object specified by the
|
|
.Fa which
|
|
argument.
|
|
Currently
|
|
.Dv CPU_WHICH_PID
|
|
is the only acceptable value for which as
|
|
threads do not have an id distinct from their process and the API does
|
|
not permit changing the id of an existing set.
|
|
Upon successful completion all of the threads in the target process will
|
|
be running on CPUs permitted by the set.
|
|
.Pp
|
|
.Fn cpuset_getid
|
|
retrieves a set id from the object indicated by
|
|
.Fa which
|
|
and stores it in the space pointed to by
|
|
.Fa setid .
|
|
The retrieved id may be that of either the root or assigned set
|
|
depending on the value of
|
|
.Fa level .
|
|
.Fa level
|
|
should be
|
|
.Dv CPU_LEVEL_CPUSET
|
|
or
|
|
.Dv CPU_LEVEL_ROOT
|
|
to get the set id from
|
|
the process or thread specified by the
|
|
.Fa id
|
|
argument.
|
|
Specifying
|
|
.Dv CPU_LEVEL_WHICH
|
|
with a process or thread is unsupported since
|
|
this references the unnumbered anonymous mask.
|
|
.Pp
|
|
The actual contents of the sets may be retrieved or manipulated using
|
|
.Xr cpuset_getaffinity 2
|
|
and
|
|
.Xr cpuset_setaffinity 2 .
|
|
See those manual pages for more detail.
|
|
.Sh RETURN VALUES
|
|
.Rv -std
|
|
.Sh ERRORS
|
|
The following error codes may be set in
|
|
.Va errno :
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa which
|
|
or
|
|
.Fa level
|
|
argument was not a valid value.
|
|
.It Bq Er EDEADLK
|
|
The
|
|
.Fn cpuset_setid
|
|
call would leave a thread without a valid CPU to run on because the set
|
|
does not overlap with the thread's anonymous mask.
|
|
.It Bq Er EFAULT
|
|
The setid pointer passed to
|
|
.Fn cpuset_getid
|
|
or
|
|
.Fn cpuset
|
|
was invalid.
|
|
.It Bq Er ESRCH
|
|
The object specified by the
|
|
.Fa id
|
|
and
|
|
.Fa which
|
|
arguments could not be found.
|
|
.It Bq Er EPERM
|
|
The calling process did not have the credentials required to complete the
|
|
operation.
|
|
.It Bq Er ENFILE
|
|
There was no free
|
|
.Ft cpusetid_t
|
|
for allocation.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr cpuset 1 ,
|
|
.Xr cpuset_getaffinity 2 ,
|
|
.Xr cpuset_setaffinity 2 ,
|
|
.Xr pthread_affinity_np 3 ,
|
|
.Xr pthread_attr_affinity_np 3
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
family of system calls first appeared in
|
|
.Fx 7.1 .
|
|
.Sh AUTHOR
|
|
.An Jeffrey Roberson Aq jeff@FreeBSD.org
|