lgrp_init(3lgrp)

1lgrp_init(3LGRP)       Locality Group Library Functions       lgrp_init(3LGRP)
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NAME

6       lgrp_init - initialize lgroup interface
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SYNOPSIS

9       cc [ flag... ] file... -llgrp [ library... ]
10       #include <sys/lgrp_user.h>
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12       lgrp_cookie_t lgrp_init(lgrp_view_t view);
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DESCRIPTION

16       The  lgrp_init()  function initializes the lgroup interface and takes a
17       snapshot of the lgroup hierarchy with the given  view.   If  the  given
18       view is LGRP_VIEW_CALLER, the snapshot contains only the resources that
19       are available to the caller (for example,  with  respect  to  processor
20       sets).  When  the  view  is LGRP_VIEW_OS, the snapshot contains what is
21       available to the operating system.
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24       Given the view, lgrp_init() returns a cookie representing this snapshot
25       of the lgroup hierarchy. This cookie should be used with other routines
26       in  the  lgroup   interface   needing   the   lgroup   hierarchy.   The
27       lgrp_fini(3LGRP)  function  should be called with the cookie when it is
28       no longer needed.
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31       The lgroup hiearchy represents the latency  topology  of  the  machine.
32       The  hierarchy  is  simplified to be a tree and can be used to find the
33       nearest resources.
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36       The lgroup hiearchy consists of a root lgroup,  which  is  the  maximum
37       bounding  locality group of the system, contains all the CPU and memory
38       resources of the machine, and may contain  other locality  groups  that
39       contain  CPUs  and  memory  within a smaller locality. The leaf lgroups
40       contain resources within the smallest latency.
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43       The resources of a given lgroup come directly from the lgroup itself or
44       from  leaf  lgroups  contained within the lgroup. Leaf lgroups directly
45       contain their own resources and do not encapsulate any other lgroups.
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48       The lgroup hierarchy can be used to find the nearest resources. From  a
49       given  lgroup, the closest resources can be found in the lgroup itself.
50       After that, the next nearest resources  can  be  found  in  its  parent
51       lgroup,  and  so  on  until  the  root  lgroup is reached where all the
52       resources of the machine are located.
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RETURN VALUES

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

59       The lgrp_init() function will fail if:
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61       EINVAL    The view is not valid.
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64       ENOMEM    There  was  not enough memory to allocate the snapshot of the
65                 lgroup hierarchy.
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ATTRIBUTES

69       See attributes(5) for descriptions of the following attributes:
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74       ┌─────────────────────────────┬─────────────────────────────┐
75       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
76       ├─────────────────────────────┼─────────────────────────────┤
77       │Interface Stability          │Evolving                     │
78       ├─────────────────────────────┼─────────────────────────────┤
79       │MT-Level                     │MT-Safe                      │
80       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

RETURN VALUES

ERRORS

ATTRIBUTES

SEE ALSO