Content-type: text/html Man page of classcntl

classcntl

Section: System Calls (2)
Index Return to Main Contents
 

NAME

classcntl - manage kernel class scheduling properties.  

SYNOPSIS

#include <sys/types.h> #include <sys/class.h>

int classcntl( int opcode, int arg1, int arg2, int arg3 );
 

PARAMETERS

Identifies the type of operation (see below). These are opcode dependent and are described below.
 

DESCRIPTION

The classcntl function is used to control kernel class scheduler functions.

Opcode and Argument Descriptions

Informs the kernel that class scheduling is turned on. The kernel will look for threads being class scheduled and charge time used against the class. Once class scheduling has been enabled, it is necessary to tell the kernel which class members to begin charging via the CL_OP_ADD_TO_CLASS opcode.

There are no arguments. Turn off class scheduling. All class members are reset to their original state. If the kernel has been notified, via CL_OP_DAEMON_ALIVE, that a class scheduler daemon has been started, that daemon will be terminated.
There are no arguments. Gets the class_list array from the kernel. The class_list array is a list of MAX_NUM_CLASSES integers.
Arguments: User buffer into which the kernel data is copied. Number of bytes to copy. Unused. Identify class members to the kernel so that their CPU usage is charged to their class.
Arguments: Class type, as in CL_TYPE_& (see class.h). Numeric value for member (gid, uid, session id, pgrp id, or pid). Index into the class_list array that represents the class. Notify the kernel that a class member's CPU time is not to be charged.
Arguments: Type as in CL_TYPE_& (see class.h). Numeric value for member (gid, uid, session id, pgrp id, or pid). Unused. Sets the class_list array into the kernel. The class_list array is a list of MAX_NUM_CLASSES integers.
Arguments: User buffer into which is copied into the kernel. Number of bytes to copy. idle_enforce -- when set to 0, a class is allowed to exceed its CPU percentage if the system would be otherwise idle. Else, a class is forced to its CPU percentage even if the system has no other work. Informs the kernel that a class_scheduler daemon is running and how often it checks class CPU usage. Should the daemon fail to run in twice the interval specified, the kernel will disable class scheduling.
Arguments: The pid of the daemon. The interval, in seconds. Unused. Returns 1 if class scheduling is currently enabled, 0 otherwise.
There are no arguments. Get the class index of a specified process id (pid).
Arguments: Pid of the target process. Address of the user data (integer) to receive the class index. Unused.
 

RESTRICTIONS

The caller must have root access rights.
 

RETURN VALUES

Unless otherwise noted above, the classcntl returns a value of zero (0) on success. The classcntl function returns -1 upon failure and sets errno to indicate the error.
 

ERRORS

The classcntl function fails under the following conditions: The Caller does not have super user privileges. Access denied -- class scheduling not enabled.
 

SEE ALSO

class_scheduling(4), runclass(1), class_admin(8)


 

Index

NAME
SYNOPSIS
PARAMETERS
DESCRIPTION
RESTRICTIONS
RETURN VALUES
ERRORS
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 02:40:15 GMT, October 02, 2010