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numa_scheduling_groups(4)
NAME
  numa_scheduling_groups - HP 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 certain 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()
       function) 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 different 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: numa_intro(3), bind_to_cpu(3), nsg_attach_pid(3),
  nsg_detach_pid(3), nsg_destroy(3), nsg_get(3), nsg_get_nsgs(3),
  nsg_get_pids(3), nsg_init(3), nsg_set(3), rad_attach_pid(3),
  rad_bind_pid(3), rad_detach_pid(3)

Index for Section 4

Alphabetical listing for N

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