numa_scheduling_groups(4)				     Kernel Interfaces Manual					 numa_scheduling_groups(4)

NAME

       numa_scheduling_groups - Compaq Tru64 UNIX NUMA Scheduling Groups description (libnuma library)

DESCRIPTION

       Normally,  the  kernel  scheduler  attempts to distribute the workload evenly over the entire machine. When the system resources are evenly
       utilized, the machine is considered to be balanced. When balancing the workload, the scheduler operates in a context-free manner; that  is,
       processes  may be distributed to various CPUs, or other resources, without regard to their function or relationship to one another. In cer-
       tain cases, a user may wish to bundle a group of processes together so that they have equal  access  to	the  same  system  resources.  For
       instance,  cooperating  processes that share the same physical memory may perform better if all of these processes execute on CPUs that are
       local to that memory.

       NUMA Scheduling Groups (NSG) cause the scheduler load-balancing system to treat all members of an NSG as a unit. If one	process  belonging
       to an NSG moves from one Resource Affinity Domain (RAD) to another, all other members of the NSG have to move with it.

       NSGs  and  their  members  have the following characteristics: The resource domain of the first process joining an NSG provides the initial
       resource domain location for that NSG, called the NSG home RAD.	All other processes joining the NSG (through  the  nsg_attach_pid()  func-
       tion) will be migrated to the NSG home RAD.  If the joining process is not allowed to migrate, the nsg_attach_pid() function will fail.	To
       support load balancing, an NSG is allowed to migrate to any RAD on the system if none of its members is bound to a specific resource  (such
       as another RAD, CPU, and so on).  An NSG member is allowed to attach to or bind to a resource only if no other members are bound to differ-
       ent resources. The entire NSG will migrate to the RAD containing the resource at the time it was successfully bound.  If one NSG member	is
       bound  to  a resource, all other members of that NSG are also bound to the RAD containing that resource, because the NSG and, therefore its
       members, is no longer allowed to migrate.

SEE ALSO

       Commands: runon(1)

       Functions: bind_to_cpu(3), nsg_attach_pid(3), nsg_detach_pid(3),  nsg_destroy(3),  nsg_get(3),  nsg_get_pids(3),  nsg_init(3),  nsg_set(3),
       numa_intro(3), rad_attach_pid(3), rad_bind_pid(3), rad_detach_pid(3)

															 numa_scheduling_groups(4)