Tribblix: manual page: Lgrp.3perl

LGRP(3PERL) Perl Library Functions LGRP(3PERL)

NAME

Lgrp - Perl interface to Solaris liblgrp library

SYNOPSIS

use Sun::Solaris::Lgrp qw(:ALL);

# initialize lgroup interface
my $cookie = lgrp_init(LGRP_VIEW_OS | LGRP_VIEW_CALLER);
my $l = Sun::Solaris::Lgrp->new(LGRP_VIEW_OS |
LGRP_VIEW_CALLER);

my $version = lgrp_version(LGRP_VER_CURRENT | LGRP_VER_NONE);
$version = $l->version(LGRP_VER_CURRENT | LGRP_VER_NONE);

$home = lgrp_home(P_PID, P_MYID);
$home = l->home(P_PID, P_MYID);

lgrp_affinity_set(P_PID, $pid, $lgrp,
LGRP_AFF_STRONG | LGRP_AFF_WEAK | LGRP_AFF_NONE);
$l->affinity_set(P_PID, $pid, $lgrp,
LGRP_AFF_STRONG | LGRP_AFF_WEAK | LGRP_AFF_NONE);

my $affinity = lgrp_affinity_get(P_PID, $pid, $lgrp);
$affinity = $l->affinity_get(P_PID, $pid, $lgrp);

my $nlgrps = lgrp_nlgrps($cookie);
$nlgrps = $l->nlgrps();

my $root = lgrp_root($cookie);
$root = l->root();

$latency = lgrp_latency($lgrp1, $lgrp2);
$latency = $l->latency($lgrp1, $lgrp2);

my @children = lgrp_children($cookie, $lgrp);
@children = l->children($lgrp);

my @parents = lgrp_parents($cookie, $lgrp);
@parents = l->parents($lgrp);

my @lgrps = lgrp_lgrps($cookie);
@lgrps = l->lgrps();

@lgrps = lgrp_lgrps($cookie, $lgrp);
@lgrps = l->lgrps($lgrp);

my @leaves = lgrp_leaves($cookie);
@leaves = l->leaves();

my $is_leaf = lgrp_isleaf($cookie, $lgrp);
$is_leaf = $l->is_leaf($lgrp);

my @cpus = lgrp_cpus($cookie, $lgrp,
LGRP_CONTENT_HIERARCHY | LGRP_CONTENT_DIRECT);
@cpus = l->cpus($lgrp, LGRP_CONTENT_HIERARCHY |
LGRP_CONTENT_DIRECT);

my $memsize = lgrp_mem_size($cookie, $lgrp,
LGRP_MEM_SZ_INSTALLED | LGRP_MEM_SZ_FREE,
LGRP_CONTENT_HIERARCHY | LGRP_CONTENT_DIRECT);
$memsize = l->mem_size($lgrp,
LGRP_MEM_SZ_INSTALLED | LGRP_MEM_SZ_FREE,
LGRP_CONTENT_HIERARCHY | LGRP_CONTENT_DIRECT);

my $is_stale = lgrp_cookie_stale($cookie);
$stale = l->stale();

lgrp_fini($cookie);

# The following is available for API version greater than 1:
my @lgrps = lgrp_resources($cookie, $lgrp, LGRP_RSRC_CPU);

# Get latencies from cookie
$latency = lgrp_latency_cookie($cookie, $from, $to);

DESCRIPTION

This module provides access to the liblgrp(3LIB) library and to
various constants and functions defined in <sys/lgrp_sys.h>. It
provides both the procedural and object interface to the library. The
procedural interface requires (in most cases) passing around a
transparent cookie. The object interface hides all the cookie
manipulations from the user.

Functions returning a scalar value indicate an error by returning
undef. The caller can examine the $! variable to get the error
value.

Functions returning a list value return the number of elements in the
list when called in scalar context. In the event of error, the empty
list is returned in the array context and undef is returned in the
scalar context.

Constants

The constants are exported with :CONSTANTS or :ALL tags:

use Sun::Solaris::Lgrp ':ALL';

or

use Sun::Solaris::Lgrp ':CONSTANTS';

The following constants are available for use in Perl programs:
LGRP_NONE
LGRP_VER_CURRENT
LGRP_VER_NONE
LGRP_VIEW_CALLER
LGRP_VIEW_OS
LGRP_AFF_NONE
LGRP_AFF_STRONG
LGRP_AFF_WEAK
LGRP_CONTENT_DIRECT
LGRP_CONTENT_HIERARCHY
LGRP_MEM_SZ_FREE
LGRP_MEM_SZ_FREE
LGRP_RSRC_CPU (1)
LGRP_RSRC_MEM (1)
LGRP_CONTENT_ALL (1)
LGRP_LAT_CPU_TO_MEM (1)
P_PID
P_LWPID
P_MYID

(1) Available for versions of the liblgrp(3LIB) API greater than 1.

Functions

A detailed description of each function follows. Since this module is
intended to provide a Perl interface to the functions in
liblgrp(3LIB), a very short description is given for the
corresponding functions in this module and a reference is given to
the complete description in the liblgrp manual pages. Any differences
or additional functionality in the Perl module are highlighted and
fully documented here.

lgrp_init([LGRP_VIEW_CALLER | LGRP_VIEW_OS])

This function initializes the lgroup interface and takes a
snapshot of the lgroup hierarchy with the given view. 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() function should be called with the cookie when it
is no longer needed. Unlike lgrp_init(3LGRP), LGRP_VIEW_OS is
assumed as the default if no view is provided.

Upon successful completion, lgrp_init() returns a cookie.
Otherwise it returns undef and sets $! to indicate the error.

See lgrp_init(3LGRP) for more information.

lgrp_fini($cookie)

This function takes a cookie, frees the snapshot of the lgroup
hierarchy created by lgrp_init(), and cleans up anything else set
up by lgrp_init(). After this function is called, the cookie
returned by the lgroup interface might no longer be valid and
should not be used.

Upon successful completion, 1 is returned. Otherwise, undef is
returned and $! is set to indicate the error.

See lgrp_fini(3LGRP) for more information.

lgrp_view($cookie)

This function takes a cookie representing the snapshot of the
lgroup hierarchy and returns the snapshot's view of the lgroup
hierarchy.

If the given view is LGRP_VIEW_CALLER, the snapshot contains only
the resources that are available to the caller (such as those
with respect to processor sets). When the view is LGRP_VIEW_OS,
the snapshot contains what is available to the operating system.

Upon successful completion, the function returns the view for the
snapshot of the lgroup hierarchy represented by the given cookie.
Otherwise, undef is returned and $! is set to indicate the error.

See lgrp_view(3LGRP) for more information.

lgrp_home($idtype, $id)

This function returns the home lgroup for the given process or
thread. The $idtype argument should be P_PID to specify a process
and the $id argument should be its process ID. Otherwise, the
$idtype argument should be P_LWPID to specify a thread and the
$id argument should be its LWP ID. The value P_MYID can be used
for the $id argument to specify the current process or thread.

Upon successful completion, lgrp_home() returns the ID of the
home lgroup of the specified process or thread. Otherwise, undef
is returned and $! is set to indicate the error.

See lgrp_home(3LGRP) for more information.

lgrp_cookie_stale($cookie)

Upon successful completion, this function returns whether the
cookie is stale. Otherwise, it returns undef and sets $! to
indicate the error.

The lgrp_cookie_stale() function will fail with EINVAL if the
cookie is not valid.

See lgrp_cookie_stale(3LGRP) for more information.

lgrp_cpus($cookie, $lgrp, $context)

This function takes a cookie representing a snapshot of the
lgroup hierarchy and returns the list of CPUs in the lgroup
specified by $lgrp. The $context argument should be set to one of
the following values to specify whether the direct contents or
everything in this lgroup including its children should be
returned:

LGRP_CONTENT_HIERARCHY
everything within this hierarchy

LGRP_CONTENT_DIRECT
directly contained in lgroup

When called in scalar context, lgrp_cpus() function returns the
number of CPUs contained in the specified lgroup.

In the event of error, undef is returned in scalar context and $!
is set to indicate the error. In list context, the empty list is
returned and $! is set.

See lgrp_cpus(3LGRP) for more information.

lgrp_children($cookie, $lgrp)

This function takes a cookie representing a snapshot of the
lgroup hierarchy and returns the list of lgroups that are
children of the specified lgroup.

When called in scalar context, lgrp_children() returns the number
of children lgroups for the specified lgroup.

In the event of error, undef or empty list is returned and $! is
set to indicate the error.

See lgrp_children(3LGRP) for more information.

lgrp_parents($cookie, $lgrp)

This function takes a cookie representing a snapshot of the
lgroup hierarchy and returns the list of parents of the specified
lgroup.

When called in scalar context, lgrp_parents() returns the number
of parent lgroups for the specified lgroup.

In the event of error, undef or an empty list is returned and $!
is set to indicate the error.

See lgrp_parents(3LGRP) for more information.

lgrp_nlgrps($cookie)

This function takes a cookie representing a snapshot of the
lgroup hierarchy. It returns the number of lgroups in the
hierarchy, where the number is always at least one.

In the event of error, undef is returned and $! is set to EINVAL,
indicating that the cookie is not valid.

See lgrp_nlgrps(3LGRP) for more information.

lgrp_root($cookie)

This function returns the root lgroup ID.

In the event of error, undef is returned and $! is set to EINVAL,
indicatng that the cookie is not valid.

See lgrp_root(3LGRP) for more information.

lgrp_mem_size($cookie, $lgrp, $type, $content)

This function takes a cookie representing a snapshot of the
lgroup hierarchy. The function returns the memory size of the
given lgroup in bytes. The $type argument should be set to one of
the following values:

LGRP_MEM_SZ_FREE
free memory

LGRP_MEM_SZ_INSTALLED
installed memory

The $content argument should be set to one of the following
values to specify whether the direct contents or everything in
this lgroup including its children should be returned:

LGRP_CONTENT_HIERARCHY
Return everything within this
hierarchy.

LGRP_CONTENT_DIRECT
Return that which is directly contained
in this lgroup.

The total sizes include all the memory in the lgroup including
its children, while the others reflect only the memory contained
directly in the given lgroup.

Upon successful completion, the size in bytes is returned.
Otherwise, undef is returned and $! is set to indicate the error.

See lgrp_mem_size(3LGRP) for more information.

lgrp_version([$version])

This function takes an interface version number, $version, as an
argument and returns an lgroup interface version. The $version
argument should be the value of LGRP_VER_CURRENT or LGRP_VER_NONE
to find out the current lgroup interface version on the running
system.

If $version is still supported by the implementation, then
lgrp_version() returns the requested version. If LGRP_VER_NONE is
returned, the implementation cannot support the requested
version.

If $version is LGRP_VER_NONE, lgrp_version() returns the current
version of the library.

The following example tests whether the version of the interface
used by the caller is supported:

lgrp_version(LGRP_VER_CURRENT) == LGRP_VER_CURRENT or
die("Built with unsupported lgroup interface");

See lgrp_version(3LGRP) for more information.

lgrp_affinity_set($idtype, $id, $lgrp, $affinity)

This function sets the affinity that the LWP or set of LWPs
specified by $idtype and $id have for the given lgroup. The
lgroup affinity can be set to LGRP_AFF_STRONG, LGRP_AFF_WEAK, or
LGRP_AFF_NONE.

If the $idtype is P_PID, the affinity is retrieved for one of the
LWPs in the process or set for all the LWPs of the process with
process ID (PID) $id. The affinity is retrieved or set for the
LWP of the current process with LWP ID $id if $idtype is P_LWPID.
If $id is P_MYID, then the current LWP or process is specified.

There are different levels of affinity that can be specified by a
thread for a particular lgroup. The levels of affinity are the
following from strongest to weakest:

LGRP_AFF_STRONG
strong affinity

LGRP_AFF_WEAK
weak affinity

LGRP_AFF_NONE
no affinity

Upon successful completion, lgrp_affinity_set() returns 1.
Otherwise, it returns undef and set $! to indicate the error.

See lgrp_affinity_set(3LGRP) for more information.

lgrp_affinity_get($idtype, $id, $lgrp)

This function returns the affinity that the LWP has to a given
lgroup.

See lgrp_affinity_get(3LGRP) for more information.

lgrp_latency_cookie($cookie, $from, $to,
[$between=LGRP_LAT_CPU_TO_MEM])

This function takes a cookie representing a snapshot of the
lgroup hierarchy and returns the latency value between a hardware
resource in the $from lgroup to a hardware resource in the $to
lgroup. If $from is the same lgroup as $to, the latency value
within that lgroup is returned.

The optional $between argument should be set to
LGRP_LAT_CPU_TO_MEM to specify between which hardware resources
the latency should be measured. The only valid value is
LGRP_LAT_CPU_TO_MEM, which represents latency from CPU to memory.

Upon successful completion, lgrp_latency_cookie() return 1.
Otherwise, it returns undef and set $! to indicate the error. For
LGRP API version 1, the lgrp_latency_cookie() is an alias for
lgrp_latency.()

See lgrp_latency_cookie(3LGRP) for more information.

lgrp_latency($from, $to)

This function is similar to the lgrp_latency_cookie() function,
but returns the latency between the given lgroups at the given
instant in time. Since lgroups can be freed and reallocated,
this function might not be able to provide a consistent answer
across calls. For that reason, lgrp_latency_cookie() should be
used in its place.

See lgrp_latency(3LGRP) for more information.

lgrp_resources($cookie, $lgrp, $type)

This function returns the list of lgroups directly containing
resources of the specified type. The resources are represented by
a set of lgroups in which each lgroup directly contains CPU
and/or memory resources.

The type can be specified as:

LGRP_RSRC_CPU
CPU resources

LGRP_RSRC_MEM
memory resources

In the event of error, undef or an empty list is returned and $!
is set to indicate the error.

This function is available only for API version 2 and returns
undef or an empty list for API version 1 and sets $! to EINVAL.

See lgrp_resources(3LGRP) for more information.

lgrp_lgrps($cookie, [$lgrp])

This function returns a list of all lgroups in a hierarchy
starting from $lgrp. If $lgrp is not specified, uses the value of
lgrp_root($cookie). This function returns the empty list on
failure.

When called in scalar context, this function returns the total
number of lgroups in the system.

lgrp_leaves($cookie, [$lgrp])

This function returns a list of all leaf lgroups in a hierarchy
starting from $lgrp. If $lgrp is not specified, this function
uses the value of lgrp_root($cookie). It returns undef or an
empty list on failure.

When called in scalar context, this function returns the total
number of leaf lgroups in the system.

lgrp_isleaf($cookie, $lgrp)

This function returns True if $lgrp is a leaf (has no children).
Otherwise it returns False.

Object methods

new([$view])

This method creates a new Sun::Solaris::Lgrp object. An optional
argument is passed to the lgrp_init() function. By default this
method uses LGRP_VIEW_OS.

cookie()

This method returns a transparent cookie that can be passed to
functions accepting the cookie.

version([$version])

Without the argument, this method returns the current version of
the liblgrp(3LIB) library. This method is a wrapper for
lgrp_version() with LGRP_VER_NONE as the default version
argument.

stale()

This method returns T if the lgroup information in the object is
stale and F otherwise. It is a wrapper for lgrp_cookie_stale().

view()

This method returns the snapshot's view of the lgroup hierarchy.
It is a wrapper for lgrp_view().

root()

This method returns the root lgroup. It is a wrapper for
lgrp_root().

children($lgrp)

This method returns the list of lgroups that are children of the
specified lgroup. It is a wrapper for lgrp_children().

parents($lgrp)

This method returns the list of lgroups that are parents of the
specified lgroup. It is a wrapper for lgrp_parents().

nlgrps()

This method returns the number of lgroups in the hierarchy. It is
a wrapper for lgrp_nlgrps().

mem_size($lgrp, $type, $content)

This method returns the memory size of the given lgroup in bytes.
It is a wrapper for lgrp_mem_size().

cpus($lgrp, $context)

This method returns the list of CPUs in the lgroup specified by
$lgrp. It is a wrapper for lgrp_cpus().

resources($lgrp, $type)

This method returns the list of lgroups directly containing
resources of the specified type. It is a wrapper for
lgrp_resources().

home($idtype, $id)

This method returns the home lgroup for the given process or
thread. It is a wrapper for lgrp_home().

affinity_get($idtype, $id, $lgrp)

This method returns the affinity that the LWP has to a given
lgrp. It is a wrapper for lgrp_affinity_get().

affinity_set($idtype, $id, $lgrp, $affinity)

This method sets the affinity that the LWP or set of LWPs
specified by $idtype and $id have for the given lgroup. It is a
wrapper for lgrp_affinity_set.

lgrps([$lgrp])

This method returns list of all lgroups in a hierarchy starting
from $lgrp or the lgrp_root() if $lgrp is not specified. It is a
wrapper for lgrp_lgrps().

leaves([$lgrp])

This method returns a list of all leaf lgroups in a hierarchy
starting from $lgrp. If $lgrp is not specified, this method uses
the value of lgrp_root(). It is a wrapper for lgrp_leaves().

isleaf($lgrp)

This method returns True if $lgrp is leaf (has no children) and
False otherwise. It is a wrapper for lgrp_isleaf().

latency($from, $to)

This method returns the latency value between a hardware resource
in the $from lgroup to a hardware resource in the $to lgroup. It
uses lgrp_latency() for version 1 of liblgrp and
lgrp_latency_cookie() for newer versions.

Exports

By default nothing is exported from this module. The following tags
can be used to selectively import constants and functions defined in
this module:

:LGRP_CONSTANTS
LGRP_AFF_NONE, LGRP_AFF_STRONG, LGRP_AFF_WEAK,
LGRP_CONTENT_DIRECT, LGRP_CONTENT_HIERARCHY,
LGRP_MEM_SZ_FREE, LGRP_MEM_SZ_INSTALLED,
LGRP_VER_CURRENT, LGRP_VER_NONE, LGRP_VIEW_CALLER,
LGRP_VIEW_OS, LGRP_NONE, LGRP_RSRC_CPU,
LGRP_RSRC_MEM, LGRP_CONTENT_ALL,
LGRP_LAT_CPU_TO_MEM

:PROC_CONSTANTS
P_PID, P_LWPID, P_MYID

:CONSTANTS
:LGRP_CONSTANTS, :PROC_CONSTANTS

:FUNCTIONS
lgrp_affinity_get(), lgrp_affinity_set(),
lgrp_children(), lgrp_cookie_stale(), lgrp_cpus(),
lgrp_fini(), lgrp_home(), lgrp_init(),
lgrp_latency(), lgrp_latency_cookie(),
lgrp_mem_size(), lgrp_nlgrps(), lgrp_parents(),
lgrp_root(), lgrp_version(), lgrp_view(),
lgrp_resources(), lgrp_lgrps(), lgrp_leaves(),
lgrp_isleaf()

:ALL
:CONSTANTS, :FUNCTIONS

Error values

The functions in this module return undef or an empty list when an
underlying library function fails. The $! is set to provide more
information values for the error. The following error codes are
possible:

EINVAL
The value supplied is not valid.

ENOMEM
There was not enough system memory to complete an
operation.

EPERM
The effective user of the calling process does not have
appropriate privileges, and its real or effective user ID
does not match the real or effective user ID of one of the
threads.

ESRCH
The specified process or thread was not found.

Difference in the API versions

The liblgrp(3LIB) library is versioned. The exact version that was
used to compile a module is available through the lgrp_version()
function.

Version 2 of the lgrp_user API introduced the following constants and
functions not present in version 1:
LGRP_RSRC_CPU constant
LGRP_RSRC_MEM constant
LGRP_CONTENT_ALL constant
LGRP_LAT_CPU_TO_MEM constant
lgrp_resources() function
lgrp_latency_cookie() function

The LGRP_RSRC_CPU and LGRP_RSRC_MEM constants are not defined for
version 1. The lgrp_resources() function is defined for version 1 but
always returns an empty list. The lgrp_latency_cookie() function is
an alias for lgrp_latency() for version 1.

ATTRIBUTES