perfstat_node_list Subroutine

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Purpose

Retrieves the list of nodes in a cluster.

Library

perfstat library (libperfstat.a)

Syntax

#include <libperfstat.h>

int perfstat_node_list  ( name, userbuff, sizeof_userbuff, desired_number)

perfstat_id_node_t *name;
perfstat_node_t *userbuff;
int sizeof_userbuff;
int desired_number;

Description

The perfstat_node_list subroutine returns the list of nodes in a perfstat_node_t structure.

The perfstat_node_list subroutine should be called only after enabling cluster statistics collection by using the following perfstat API call: perfstat_config(PERFSTAT_ENABLE | PERFSTAT_CLUSTER_STATS, NULL).

The cluster statistics collection must be disabled after collecting the node list by using the following perfstat API call: perfstat_config(PERFSTAT_DISABLE | PERFSTAT_CLUSTER_STATS, NULL).

To obtain the total number of nodes in a cluster (in which the current node is participating), the cluster name must be specified in the name parameter, the userbuff parameter must be specified as NULL and the desired_number parameter must be specified as zero.

To obtain the list of nodes in a particular cluster (in which the current node is participating), the cluster name must be specified in the name parameter. The userbuff parameter must be allocated. The desired_number parameter must be set.

Note: The cluster name should be one of the clusters in which the current node (in which the perfstat API call is run) is participating.

Parameters

Item Description
name.nodenamename.spec

Specifies the cluster name.

Specifies the Cluster ID specifier. Should be set to CLUSTERNAME.
userbuff Specifies the memory area that is to be filled with the perfstat_node_t structure.
sizeof_userbuff Specifies the size of the perfstat_node_t structure.
desired_number Specifies the number of structures to be returned.

Return Values

Unless the perfstat_node_list subroutine is used to retrieve the number of available structures, the number of structures filled is returned upon successful completion. If unsuccessful, a value of -1 is returned and the errno global variable is set.

Error Codes

The subroutine is unsuccessful if the following is true:

Item Description
EINVAL One of the parameters is not valid.
ENOENT Either cluster statistics collection is not enabled using perfstat_config or cluster statistics collection is currently not supported.

Files

The libperfstat.h file defines standard macros, data types, and subroutines.