xref: /illumos-gate/usr/src/man/man3lgrp/lgrp_init.3lgrp (revision 9fc69cd99026dc35cc62ad524193fa0dfd4de20f)
te
Copyright (c) 2005, Sun Microsystems, Inc. All Rights Reserved.
The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
LGRP_INIT 3LGRP "Jan 26, 2005"
NAME
lgrp_init - initialize lgroup interface
SYNOPSIS

cc [ flag... ] file.\|.\|. -llgrp [ library... ]
#include <sys/lgrp_user.h>

lgrp_cookie_t lgrp_init(lgrp_view_t view);
DESCRIPTION

The lgrp_init() function initializes the lgroup interface and takes a snapshot of the lgroup hierarchy with the given view. If the given view is LGRP_VIEW_CALLER, the snapshot contains only the resources that are available to the caller (for example, with respect to processor sets). When the view is LGRP_VIEW_OS, the snapshot contains what is available to the operating system.

Given the view, lgrp_init() returns a cookie representing this snapshot of the lgroup hierarchy. This cookie should be used with other routines in the lgroup interface needing the lgroup hierarchy. The lgrp_fini(3LGRP) function should be called with the cookie when it is no longer needed.

The lgroup hiearchy represents the latency topology of the machine. The hierarchy is simplified to be a tree and can be used to find the nearest resources.

The lgroup hiearchy consists of a root lgroup, which is the maximum bounding locality group of the system, contains all the CPU and memory resources of the machine, and may contain other locality groups that contain CPUs and memory within a smaller locality. The leaf lgroups contain resources within the smallest latency.

The resources of a given lgroup come directly from the lgroup itself or from leaf lgroups contained within the lgroup. Leaf lgroups directly contain their own resources and do not encapsulate any other lgroups.

The lgroup hierarchy can be used to find the nearest resources. From a given lgroup, the closest resources can be found in the lgroup itself. After that, the next nearest resources can be found in its parent lgroup, and so on until the root lgroup is reached where all the resources of the machine are located.

RETURN VALUES

Upon successful completion, lgrp_init() returns a cookie. Otherwise it returns LGRP_COOKIE_NONE and sets errno to indicate the error.

ERRORS

The lgrp_init() function will fail if: EINVAL

The view is not valid.

ENOMEM

There was not enough memory to allocate the snapshot of the lgroup hierarchy.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Evolving
MT-Level MT-Safe
SEE ALSO

lgrp_children(3LGRP), lgrp_cookie_stale(3LGRP), lgrp_cpus(3LGRP), lgrp_fini(3LGRP), lgrp_mem_size(3LGRP), lgrp_nlgrps(3LGRP), lgrp_parents(3LGRP), lgrp_resources(3LGRP), lgrp_root(3LGRP), lgrp_view(3LGRP), liblgrp(3LIB), attributes(5)