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classcntl(2) System Calls Manual classcntl(2) 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). are opcode dependent and are described below. DESCRIPTION The classcntl function is used to control kernel class scheduler func- tions. 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. none. 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. none. Gets the class_list array from the kernel. The class_list array is a list of MAX_NUM_CLASSES integers. arg1 User buffer into which the kernel data is copied. arg2 Number of bytes to copy. arg3 Unused. Identify class members to the kernel so that their CPU usage is charged to their class. arg1 Class type, as in CL_TYPE_XXX (see class.h). arg2 Numeric value for member (gid, uid, session id, pgrp id, or pid). arg3 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. arg1 Type as in CL_TYPE_XXX (see class.h). arg2 Numeric value for member (gid, uid, session id, pgrp id, or pid). arg3 Unused. Sets the class_list array into the kernel. The class_list array is a list of MAX_NUM_CLASSES integers. arg1 User buffer into which is copied into the kernel. arg2 Number of bytes to copy. arg3 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 of- ten it checks class CPU usage. Should the daemon fail to run in twice the interval specified, the kernel will disable class scheduling. arg1 The pid of the daemon. arg2 The interval, in seconds. arg3 Unused. Returns 1 if class scheduling is currently enabled, 0 otherwise. none Get the class index of a specified process id (pid). arg1 Pid of the target process. arg2 Address of the user data (integer) to receive the class index. arg3 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. Upon failure, the classcntl function returns -1 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. RELATED INFORMATION class_scheduling(4), runclass(1), class_admin(8). delim off delim off classcntl(2)