cpuset(4)							     cpuset(4)

NAME    [Toc]    [Back]

     cpuset, miser_cpuset - cpuset configuration files

DESCRIPTION    [Toc]    [Back]

     A cpuset is defined by a cpuset configuration file	and a name.  The
     cpuset configuration file is used to list the CPUs	that are members of
     the cpuset	and contains any additional parameters needed to define	the
     cpuset.  The file permissions of the configuration	file define access to
     the cpuset.  Every	time permissions need to be checked, the current
     permissions of the	file are used.	It is therefore	possible to change
     access to a particular cpuset, without having to tear it down and
     recreate it, simply by changing the access	permissions. Read access
     allows a user to retrieve information about a cpuset while	execute
     permission	allows the user	to attach a process to the cpuset.

     The name of the cpuset is a three to eight	character string.  Queue names
     having one	or two characters are reserved for use by IRIX.

     For information on	how to use cpusets in a	Trusted	IRIX environment, see
     the cpuset(1) man page.

EXAMPLE    [Toc]    [Back]

     The following configuration file describes	an exclusive cpuset containing
     4 CPUs:

     #cpuset configuration file
     EXCLUSIVE
     MEMORY_LOCAL
     MEMORY_EXCLUSIVE

     CPU 16    [Toc]    [Back]
     CPU 17
     CPU 18
     CPU 19


     This specification	will create a cpuset containing	4 CPUs,	and will
     restrict those cpus to running threads that have been explicitly assigned
     to	the cpuset.  Jobs running on the cpuset	will use memory	from nodes
     containing	the cpus in the	cpuset.	 Jobs running on other cpusets or on
     the global	cpuset will not	use memory from	these nodes.

SUMMARY    [Toc]    [Back]

     Commands are newline terminated, characters following the comment
     delimiter '#' are ignored,	case matters, and tokens are separated by
     whitespace	which is ignored.

     The valid tokens are:

     EXCLUSIVE    [Toc]    [Back]
	  Defines a cpuset to be restricted.  It can occur anywhere in the
	  file.	 Anything else on the line is ignored.



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cpuset(4)							     cpuset(4)



     MEMORY_LOCAL    [Toc]    [Back]
	  Threads assigned to the cpuset will attempt to assign	memory only
	  from nodes within the	cpuset.	 Assignment of memory from outside the
	  cpuset will occur only if no free memory is available	from within
	  the cpuset.  No restrictions are made	on memory assignment to
	  threads running outside the cpuset.

     MEMORY_EXCLUSIVE    [Toc]    [Back]
	  Threads not assigned to the cpuset will not use memory from within
	  the cpuset unless no memory outside the cpuset is available.

	  If, at the time a cpuset is created, memory is already assigned to
	  threads that are already running, no attempt will be made to
	  explicitly move this memory.	If page	migration is enabled, the
	  pages	will be	migrated when the system detects that most references
	  to the pages are non-local.

     MEMORY_KERNEL_AVOID    [Toc]    [Back]
	  The kernel will attempt to avoid allocating memory from nodes
	  contained in this cpuset.  If	kernel memory requests cannot be
	  satisfied from outside this cpuset, this option will be ignored and
	  allocations will occur from within the cpuset.

	  WARNING: It is strongly recommended that this	option not be used for
	  most cpuset configurations.  A side effect of	this option is that
	  kernel memory	allocations become concentrated	on the remaining
	  system nodes,	which may in turn degrade system performance.  This
	  option is effective only for certain workload	patterns, and could
	  cause	severe performance penalties in	other situations.  It is
	  recommended that this	option be used only when indicated by SGI
	  support.

	  Currently this option	prevents only the system buffer	cache from
	  being	placed on the specified	nodes.	Future IRIX releases may
	  expand the scope of this protection to exclude other kernel memory
	  allocations from the specified nodes.

	  This option was introduced in	IRIX 6.5.7.

     MEMORY_MANDATORY    [Toc]    [Back]
	  The kernel will limit	all memory allocations to nodes	that are
	  contained in this cpuset.  If	memory requests	cannot be satisfied,
	  the allocating process will sleep until memory is available.	The
	  process will be killed if no more memory can be allocated.  See
	  policies below.

     POLICY_PAGE    [Toc]    [Back]
	  Requires MEMORY_MANDATORY.  This is the default policy if no policy
	  is specified.	 This policy will cause	the kernel to page user	pages
	  to the swap file (see	swap(1M)) to free physical memory on the nodes
	  contained in this cpuset.  If	swap space is exhausted, the process
	  will be killed.



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cpuset(4)							     cpuset(4)



     POLICY_KILL    [Toc]    [Back]
	  Requires MEMORY_MANDATORY.  The kernel will attempt to free as much
	  space	as possible from kernel	heaps, but will	not page user pages to
	  the swap file.  If all physical memory on the	nodes contained	in
	  this cpuset are exhausted, the process will be killed.

     CPU cpuid
	  Specifies a CPU that will be part of the cpuset.

NOTES    [Toc]    [Back]

     In	a cluster environment, the cpuset configuration	file should reside on
     the root filesystem. If the cpuset	configuration file resides on a
     filesystem	other than the root filesystem and  you	attempt	to unmount the
     filesystem, the vnode for the cpuset remains active and the unmount (see
     mount(1M) command fails.

     Make sure that your workload manager sets the configuration file to
     reside on the root	filesystem.

SEE ALSO    [Toc]    [Back]

     cpuset(1),	cpuset(5).

     IRIX Admin: Resource Administration


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