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priocntl(2)			 System	Calls			   priocntl(2)

NAME
       priocntl	- process scheduler control

SYNOPSIS
       #include	<sys/types.h>
       #include	<sys/priocntl.h>
       #include	<sys/rtpriocntl.h>
       #include	<sys/tspriocntl.h>
       #include	<sys/fsspriocntl.h>
       #include	<sys/fxpriocntl.h>

       long priocntl(idtype_t idtype, id_t id, int cmd,	/* arg */ ...);

DESCRIPTION
       The  priocntl() function	provides for control over the scheduling of an
       active light weight process (LWP).

       LWPs fall into distinct classes with a separate scheduling  policy  ap-
       plied  to  each class. The classes currently supported are the realtime
       class, the time-sharing class, the fair-share class, and	the fixed-pri-
       ority  class.  The characteristics of these classes are described under
       the corresponding headings below.

       The class attribute of an LWP is	inherited across the fork(2)  function
       and  the	 exec(2)  family  of functions.	The priocntl() function	can be
       used to dynamically change the class and	 other	scheduling  parameters
       associated with a running LWP or	set of LWPs given the appropriate per-
       missions	as explained below.

       In the default configuration, a runnable	realtime LWP runs  before  any
       other LWP. Therefore, inappropriate use of realtime LWP can have	a dra-
       matic negative impact on	system performance.

       The priocntl() function provides	an interface for specifying a process,
       set  of	processes, or an LWP to	which the function applies. The	prioc-
       ntlset(2) function provides the same functions as priocntl(),  but  al-
       lows  a	more general interface for specifying the set of LWPs to which
       the function is to apply.

       For priocntl(), the idtype and id arguments are used together to	 spec-
       ify  the	 set of	LWPs. The interpretation of id depends on the value of
       idtype. The possible values for idtype  and  corresponding  interpreta-
       tions of	id are as follows:

       P_ALL	       The  priocntl()	function applies to all	existing LWPs.
		       The value of id is ignored. The permission restrictions
		       described below still apply.

       P_CID	       The  id	argument is a class ID (returned by the	prioc-
		       ntl() PC_GETCID command as explained below). The	prioc-
		       ntl()  function	applies	 to  all LWPs in the specified
		       class.

       P_GID	       The id argument is a group ID. The priocntl()  function
		       applies to all LWPs with	this effective group ID.

       P_LWPID	       The id argument is an LWP ID. The priocntl function ap-
		       plies to	the LWP	with the specified ID within the call-
		       ing process.

       P_PGID	       The  id	argument is a process group ID.	The priocntl()
		       function	applies	to all LWPs currently associated  with
		       processes in the	specified process group.

       P_PID	       The  id	argument  is  a	process	ID specifying a	single
		       process.	The priocntl() function	applies	 to  all  LWPs
		       currently associated with the specified process.

       P_PPID	       The  id argument	is a parent process ID.	The priocntl()
		       function	applies	to all LWPs currently associated  with
		       processes with the specified parent process ID.

       P_PROJID	       The  id	argument is a project ID. The priocntl() func-
		       tion applies to all LWPs	with this project ID.

       P_SID	       The id argument is a session ID.	The  priocntl()	 func-
		       tion applies to all LWPs	currently associated with pro-
		       cesses in the specified session.

       P_TASKID	       The id argument is a task ID. The  priocntl()  function
		       applies to all LWPs currently associated	with processes
		       in the specified	task.

       P_UID	       The id argument is a user ID. The  priocntl()  function
		       applies to all LWPs with	this effective user ID.

       P_ZONEID	       The  id	argument is a zone ID. The priocntl() function
		       applies to all LWPs with	this zone ID.

       P_CTID	       The id argument is a process contract  ID.  The	prioc-
		       ntl()  function	applies	 to all	LWPs with this process
		       contract	ID.

       An id value of P_MYID can be used in conjunction	with the idtype	 value
       to specify the LWP ID, parent process ID, process group ID, session ID,
       task ID,	class ID, user ID, group ID, project ID, zone ID,  or  process
       contract	ID of the calling LWP.

       To change the scheduling	parameters of an LWP (using the	PC_SETPARMS or
       PC_SETXPARMS command as explained below)	, the real or  effective  user
       ID of the LWP calling priocntl()	must match the real or the calling LWP
       must have sufficient privileges.	 These are the minimum permission  re-
       quirements  enforced  for all classes. An individual class might	impose
       additional permissions requirements when	setting	 LWPs  to  that	 class
       and/or when setting class-specific scheduling parameters.

       A special SYS scheduling	class exists for the purpose of	scheduling the
       execution of certain special system  processes  (such  as  the  swapper
       process).  It is	not possible to	change the class of any	LWP to SYS. In
       addition, any processes in the SYS class	that are included in a	speci-
       fied  set  of processes are disregarded by  priocntl(). For example, an
       idtype of P_UID and an id value of 0 would specify all processes	with a
       user ID of 0 except processes in	the SYS	class and (if changing the pa-
       rameters	using PC_SETPARMS or PC_SETXPARMS) the	init(1M) process.

       The init	process	is a special case. For a priocntl() call to change the
       class  or  other	 scheduling parameters of the init process (process ID
       1), it must be the only process specified by idtype and id.   The  init
       process	can be assigned	to any class configured	on the system, but the
       time-sharing class is almost  always  the  appropriate  choice.	(Other
       choices	might  be  highly  undesirable.	 See the System	Administration
       Guide: Basic Administration for more information.)

       The data	type and value of arg are specific  to	the  type  of  command
       specified by cmd.

       A pcinfo_t structure with the following members,	defined	in <sys/prioc-
       ntl.h>, is used by the PC_GETCID	and PC_GETCLINFO commands.

       id_t   pc_cid;			/* Class id */
       char   pc_clname[PC_CLNMSZ];	/* Class name */
       int    pc_clinfo[PC_CLINFOSZ];	/* Class information */

       The pc_cid member is a class ID returned	by  the	 priocntl()  PC_GETCID
       command.	  The  pc_clname member	is a buffer of size PC_CLNMSZ, defined
       in <sys/priocntl.h>, used to hold the class name: RT for	 realtime,  TS
       for time-sharing, or FX for fixed-priority.

       The  pc_clinfo  member  is  a  buffer  of  size PC_CLINFOSZ, defined in
       <sys/priocntl.h>, used to return	data describing	the  attributes	 of  a
       specific	 class.	 The  format of	this data is class-specific and	is de-
       scribed under the appropriate  heading  (REALTIME  CLASS,  TIME-SHARING
       CLASS, or FIXED-PRIORITY	CLASS) below.

       A  pcparms_t structure with the following members, defined in <sys/pri-
       ocntl.h>, is used by the	PC_SETPARMS and	PC_GETPARMS commands.

       id_t  pc_cid;		       /* LWP class */
       int   pc_clparms[PC_CLPARMSZ];  /* Class-specific params	*/

       The pc_cid member is a class ID returned	by  the	 priocntl()  PC_GETCID
       command.	 The special class ID PC_CLNULL	can also be assigned to	pc_cid
       when using the PC_GETPARMS command as explained below.

       The pc_clparms buffer holds class-specific scheduling  parameters.  The
       format of this parameter	data for a particular class is described under
       the appropriate	heading	 below.	 PC_CLPARMSZ  is  the  length  of  the
       pc_clparms buffer and is	defined	in <sys/priocntl.h>.

       The PC_SETXPARMS	and PC_GETXPARMS commands exploit the varargs declara-
       tion of priocntl(). The argument	following the command code is a	 class
       name:  RT  for realtime,	TS for time-sharing, or	FX for fixed-priority.
       The parameters  after the class name build  a  chain  of	 (key,	value)
       pairs,  where  the  key	determines the meaning of the value within the
       pair. When using	PC_GETXPARMS, the value	associated with	the key	is al-
       ways  a	pointer	 to  a	scheduling parameter.  In contrast, when using
       PC_SETXPARMS the	scheduling parameter is	given as a  direct  value.   A
       key  value  of 0	terminates the sequence	and all	further	keys or	values
       are ignored.

       The  PC_SETXPARMS  and  PC_GETXPARMS   commands	 are   more   flexible
       thanPC_SETPARMS	and  PC_GETPARMS  and  should  replace PC_SETPARMS and
       PC_GETPARMS on a	long-term basis.

COMMANDS
       Available priocntl() commands are:

       PC_ADMIN	       This command provides functionality needed for the  im-
		       plementation  of	 the  dispadmin(1M) utility. It	is not
		       intended	for general use	by other applications.

       PC_DONICE       Set or get nice value of	the specified  LWP(s)  associ-
		       ated  with the specified	process(es). When this command
		       is used with the	idtype of P_LWPID, it  sets  the  nice
		       value  of  the LWP. The arg argument points to a	struc-
		       ture of type pcnice_t. The pc_val member	specifies  the
		       nice  value and the pc_op specifies the type of the op-
		       eration.

		       When pc_op is set to PC_GETNICE,	 priocntl()  sets  the
		       pc_val to the highest priority (lowest numerical	value)
		       pertaining to any of the	specified LWPs.

		       When pc_op is set to PC_SETNICE,	 priocntl()  sets  the
		       nice  value  of	all  LWPs  in the specified set	to the
		       value specified in pc_val member	of pcnice_t structure.

		       The priocntl() function returns -1 with	errno  set  to
		       EPERM  if the calling LWP doesn't have appropriate per-
		       missions	to set or get nice values for one or  more  of
		       the  target  LWPs.  If  priocntl()  encounters an error
		       other than permissions, it does	not  continue  through
		       the  set	 of  target LWPs but returns the error immedi-
		       ately.

       PC_GETCID       Get class ID and	class attributes for a specific	 class
		       given  the  class name. The idtype and id arguments are
		       ignored.	If arg is non-null, it points to  a  structure
		       of  type	 pcinfo_t.  The	 pc_clname buffer contains the
		       name of the class whose attributes you are getting.

		       On success, the class ID	is  returned  in  pc_cid,  the
		       class  attributes are returned in the pc_clinfo buffer,
		       and the priocntl() call returns	the  total  number  of
		       classes	configured  in	the  system (including the sys
		       class). If the class specified by pc_clname is  invalid
		       or is not currently configured, the priocntl() call re-
		       turns -1	with errno set to EINVAL. The  format  of  the
		       attribute data returned for a given class is defined in
		       the <sys/rtpriocntl.h>, <sys/tspriocntl.h>, or <sys/fx-
		       priocntl.h>  header and described under the appropriate
		       heading below.

		       If arg is a null	pointer, no attribute data is returned
		       but  the	 priocntl()  call  still returns the number of
		       configured classes.

       PC_GETCLINFO    Get class name and  class  attributes  for  a  specific
		       class  given  class ID. The idtype and id arguments are
		       ignored.	If arg is non-null, it points to  a  structure
		       of  type	pcinfo_t. The pc_cid member is the class ID of
		       the class whose attributes you are getting.

		       On success, the class name is returned in the pc_clname
		       buffer,	the  class  attributes	are  returned  in  the
		       pc_clinfo buffer, and the priocntl() call  returns  the
		       total  number  of classes configured in the system (in-
		       cluding the sys class). The  format  of	the  attribute
		       data  returned  for  a  given  class  is	defined	in the
		       <sys/rtpriocntl.h>, <sys/tspriocntl.h>, or  <sys/fxpri-
		       ocntl.h>	 header	 and  described	 under the appropriate
		       heading below.

		       If arg is a null	pointer, no attribute data is returned
		       but  the	 priocntl()  call  still returns the number of
		       configured classes.

       PC_GETPARMS     Get the class and/or class-specific scheduling  parame-
		       ters of an LWP. The arg member points to	a structure of
		       type pcparms_t.

		       If pc_cid specifies a configured	class and a single LWP
		       belonging to that class is specified  by	the idtype and
		       id values or the	procset	structure, then	the scheduling
		       parameters  of  that LWP	are returned in	the pc_clparms
		       buffer. If the LWP specified does not exist or does not
		       belong  to the specified	class, the priocntl() call re-
		       turns -1	with errno set to ESRCH.

		       If pc_cid specifies a configured	class  and  a  set  of
		       LWPs  is	specified, the scheduling parameters of	one of
		       the specified LWP belonging to the specified class  are
		       returned	 in  the  pc_clparms buffer and	the priocntl()
		       call returns the	process	ID of the  selected  LWP.  The
		       criteria	for selecting an LWP to	return in this case is
		       class-dependent.	If none	of the specified LWPs exist or
		       none  of	them belong to the specified class, the	prioc-
		       ntl() call returns -1 with errno	set to ESRCH.

		       If pc_cid is PC_CLNULL and a single LWP	is  specified,
		       the  class  of  the specified LWP is returned in	pc_cid
		       and its	scheduling  parameters	are  returned  in  the
		       pc_clparms buffer.

       PC_GETXPARMS    Get  the	 class or class-specific scheduling parameters
		       of  an  LWP.  The  class	 name  (first  argument	 after
		       PC_GETXPARMS)  specifies	the class and the (key,	value)
		       pair sequence contains a	pointer	to the	class-specific
		       parameters.  The	 keys  and the types of	the class-spe-
		       cific parameter data  are described below and can  also
		       be  found  in  the class-specific headers <sys/rtprioc-
		       ntl.h>, <sys/tspriocntl.h>, and <sys/fxpriocntl.h>.  If
		       the  specified class is a configured class and a	single
		       LWP belonging to	that class is specified	by the	idtype
		       and id values or	the procset structure, then the	sched-
		       uling parameters	of that	LWP are	returned in the	 given
		       (key,  value)  pair  buffers. If	the LWP	specified does
		       not exist or does not belong to	the  specified	class,
		       priocntl() returns -1 and errno is set to ESRCH.

		       If  the	class  name specifies a	configured class and a
		       set of LWPs is given, the scheduling parameters of  one
		       of  the specified LWPs belonging	to the specified class
		       are  returned  and  the	priocntl()  call  returns  the
		       process	ID  of	the selected LWP. The criteria for se-
		       lecting an LWP to return	in this	case  is  class-depen-
		       dent.  If  none	of the specified LWPs exist or none of
		       them belong to the specified class, priocntl()  returns
		       -1 and errno is set to ESRCH.

		       If  the	class name is a	null pointer, a	single process
		       or LWP is specified, and	a  (key,  value)  pair	for  a
		       class  name request is given, priocntl()	fills the buf-
		       fer pointed to by value with  the  class	 name  of  the
		       specified  process  or  LWP. The	key for	the class name
		       request is  PC_KY_CLNAME	 and  the  class  name	buffer
		       should be declared as:

		       char   pc_clname[PC_CLNMSZ];	/* Class name */

       PC_SETPARMS     Set  the	class and class-specific scheduling parameters
		       of the specified	LWP(s) associated with	the  specified
		       process(es). When this command is used with the	idtype
		       of P_LWPID, it will set the  class  and	class-specific
		       scheduling  parameters  of  the	LWP.  The arg argument
		       points to a structure of	 type  pcparms_t.  The	pc_cid
		       member  specifies  the  class  you  are setting and the
		       pc_clparms buffer contains the  class-specific  parame-
		       ters you	are setting.  The format of the	class-specific
		       parameter data is defined  in  the  <sys/rtpriocntl.h>,
		       <sys/tspriocntl.h>,  or	<sys/fxpriocntl.h>  header and
		       described under the appropriate class heading below.

		       When setting parameters for a set of  LWPs,  priocntl()
		       acts  on	 the LWPs in the set in	an implementation-spe-
		       cific order. If priocntl() encounters an	error for  one
		       or  more	of the target processes, it might or might not
		       continue	through	the set	of LWPs, depending on the  na-
		       ture  of	 the error. If the error is related to permis-
		       sions (EPERM), priocntl()  continues  through  the  LWP
		       set,  resetting	the parameters for all target LWPs for
		       which the calling LWP has appropriate permissions.  The
		       priocntl()  function  then returns -1 with errno	set to
		       EPERM to	indicate that the operation failed for one  or
		       more  of	 the  target LWPs. If priocntl() encounters an
		       error other than	 permissions,  it  does	 not  continue
		       through	the  set  of target LWPs but returns the error
		       immediately.

       PC_SETXPARMS    Set the class and class-specific	scheduling  parameters
		       of  the specified LWP(s)	 associated with the specified
		       process(es). When this command is used with P_LWPID  as
		       idtype, it will set the class and class-specific	sched-
		       uling parameters	of the LWP. The	class name (first  ar-
		       gument  after  PC_SETXPARMS)  specifies the class to be
		       changed and the following (key,	value)	pair  sequence
		       contains	 the  class-specific parameters	to be changed.
		       Only those (key,value) pairs whose scheduling  behavior
		       is  to change must be specified.	The keys and the types
		       of the class-specific parameter data are	described  be-
		       low  and	can also be found in the class-specific	header
		       files   <sys/rtpriocntl.h>,   <sys/tspriocntl.h>,   and
		       <sys/fxpriocntl.h>.

		       When  setting  parameters for a set of LWPs, priocntl()
		       acts on the LWPs	in the set in  an  implementation-spe-
		       cific  order. If	priocntl() encounters an error for one
		       or more of the target processes,	it might or might  not
		       continue	 through the set of LWPs, depending on the na-
		       ture of the error. If the error is related  to  permis-
		       sions (EPERM), priocntl() continues to reset the	param-
		       eters for all target LWPs where the calling LWP has ap-
		       propriate  permissions. The priocntl() function returns
		       -1 and errno is set to EPERM when the operation	failed
		       for  one	 or  more of the target	LWPs. All errors other
		       than EPERM result in an immediate termination of	prioc-
		       ntl().

REALTIME CLASS
       The realtime class provides a fixed priority preemptive scheduling pol-
       icy for those LWPS requiring fast and deterministic response and	 abso-
       lute user/application control of	scheduling priorities. If the realtime
       class is	configured in the system, it should have exclusive control  of
       the  highest range of scheduling	priorities on the system. This ensures
       that a runnable realtime	LWP is given CPU service before	 any  LWP  be-
       longing to any other class.

       The  realtime  class  has  a range of realtime priority (rt_pri)	values
       that can	be assigned to an LWP within the  class.  Realtime  priorities
       range  from 0 to	x, where the value of x	is configurable	and can	be de-
       termined	for a specific installation by using the priocntl()  PC_GETCID
       or PC_GETCLINFO command.

       The realtime scheduling policy is a fixed priority policy. The schedul-
       ing priority of a realtime LWP is never changed except as the result of
       an  explicit request by the user/application to change the rt_pri value
       of the LWP.

       For an LWP in the realtime class, the rt_pri value is, for all  practi-
       cal  purposes,  equivalent  to  the scheduling priority of the LWP. The
       rt_pri value completely determines the scheduling priority of  a	 real-
       time  LWP  relative  to other LWPs within its class. Numerically	higher
       rt_pri values represent higher priorities.  Since  the  realtime	 class
       controls	 the  highest range of scheduling priorities in	the system, it
       is guaranteed that the runnable realtime	LWP with  the  highest	rt_pri
       value is	always selected	to run before any other	LWPs in	the system.

       In addition to providing	control	over priority, priocntl() provides for
       control over the	length of the time quantum allotted to the LWP in  the
       realtime	 class.	The time quantum value specifies the maximum amount of
       time an LWP can run assuming that it does not complete or enter	a  re-
       source  or event	wait state (sleep). If another LWP becomes runnable at
       a higher	priority, the currently	running	LWP might be preempted	before
       receiving its full time quantum.

       The realtime quantum signal can be used for the notification of runaway
       realtime	processes about	the consumption	of their time  quantum.	 Those
       processes, which	are monitored by the realtime time quantum signal, re-
       ceive the configured signal in the event	of  time  quantum  expiration.
       The  default value (0) of the time quantum signal will denote no	signal
       delivery	and a positive value will denote the delivery  of  the	signal
       specified by the	value. The realtime quantum signal can be set with the
       priocntl() PC_SETXPARMS	command	 and  displayed	 with  the  priocntl()
       PC_GETXPARMS command as explained below.

       The  system's  process  scheduler keeps the runnable realtime LWPs on a
       set of scheduling queues. There is a separate queue for each configured
       realtime	 priority  and all realtime LWPs with a	given rt_pri value are
       kept together on	the appropriate	queue. The LWPs	on a given  queue  are
       ordered	in  FIFO order (that is, the LWP at the	front of the queue has
       been waiting longest for	service	and receives the CPU first).  Realtime
       LWPs  that  wake	 up  after  sleeping, LWPs that	change to the realtime
       class from some other class, LWPs that have used	their full time	 quan-
       tum,  and  runnable  LWPs whose priority	is reset by priocntl() are all
       placed at the back of the appropriate queue for their priority. An  LWP
       that  is	preempted by a higher priority LWP remains at the front	of the
       queue (with whatever time is remaining in its time  quantum)  and  runs
       before  any  other  LWP	at this	priority. Following a fork(2) function
       call by a realtime LWP, the parent LWP continues	to run while the child
       LWP (which inherits its parent's	rt_pri value) is placed	at the back of
       the queue.

       A rtinfo_t structure with the following members,	defined	in <sys/rtpri-
       ocntl.h>,  defines the format used for the attribute data for the real-
       time class.

       short	rt_maxpri;	/* Maximum realtime priority */

       The priocntl() PC_GETCID	 and  PC_GETCLINFO  commands  return  realtime
       class attributes	in the pc_clinfo buffer	in this	format.

       The  rt_maxpri member specifies the configured maximum rt_pri value for
       the realtime class. If rt_maxpri	is x, the  valid  realtime  priorities
       range from 0 to x.

       A  rtparms_t  structure with the	following members, defined in <sys/rt-
       priocntl.h>, defines the	format used to specify the realtime class-spe-
       cific scheduling	parameters of an LWP.

       short	rt_pri;	      /* Real-Time priority */
       uint_t	rt_tqsecs;    /* Seconds in time quantum */
       int	rt_tqnsecs;   /* Additional nanoseconds	in quantum */

       When  using  the	 priocntl()  PC_SETPARMS  or  PC_GETPARMS commands, if
       pc_cid specifies	the realtime class, the	data in	the pc_clparms	buffer
       are in this format.

       These  commands	can be used to set the realtime	priority to the	speci-
       fied value or get the current rt_pri value. Setting the rt_pri value of
       an  LWP that is currently running or runnable (not sleeping) causes the
       LWP to be placed	at the back of the scheduling queue for	the  specified
       priority.  The  LWP  is placed at the back of the appropriate queue re-
       gardless	of whether the priority	being set is different from the	previ-
       ous  rt_pri value of the	LWP. A running LWP can voluntarily release the
       CPU and go to the back of the scheduling	queue at the same priority  by
       resetting  its  rt_pri value to its current realtime priority value. To
       change the time quantum of an LWP without setting the priority  or  af-
       fecting	the  LWP's  position on	the queue, the rt_pri member should be
       set to the special value	RT_NOCHANGE,  defined  in  <sys/rtpriocntl.h>.
       Specifying  RT_NOCHANGE	when  changing the class of an LWP to realtime
       from some other class results in	the realtime priority being set	to 0.

       For the priocntl() PC_GETPARMS command, if pc_cid specifies  the	 real-
       time  class and more than one realtime LWP is specified,	the scheduling
       parameters of the realtime LWP with the highest rt_pri value among  the
       specified  LWPs	are returned and the LWP ID of this LWP	is returned by
       the priocntl() call. If there is	more than one LWP sharing the  highest
       priority, the one returned is implementation-dependent.

       The  rt_tqsecs  and  rt_tqnsecs members are used	for getting or setting
       the time	quantum	associated with	an LWP or group	of LWPs. rt_tqsecs  is
       the  number of seconds in the time quantum and rt_tqnsecs is the	number
       of  additional  nanoseconds  in	the  quantum.  For  example,   setting
       rt_tqsecs  to 2 and rt_tqnsecs to 500,000,000 (decimal) would result in
       a time quantum of two and  one-half  seconds.  Specifying  a  value  of
       1,000,000,000  or  greater in the rt_tqnsecs member results in an error
       return with errno  set  to  EINVAL.  Although  the  resolution  of  the
       tq_nsecs	 member	 is  very  fine,  the specified	time quantum length is
       rounded up by the system	to the next integral multiple  of  the	system
       clock's	resolution.  The maximum time quantum that can be specified is
       implementation-specific and equal to INT_MAX1 ticks. The	INT_MAX	 value
       is  defined in <limits.h>. Requesting a quantum greater than this maxi-
       mum results in an error return with errno set to	ERANGE,	although infi-
       nite  quantums  can be requested	using a	special	value as explained be-
       low. Requesting a time quantum of  0  by	 setting  both	rt_tqsecs  and
       rt_tqnsecs to 0 results in an error return with errno set to EINVAL.

       The  rt_tqnsecs	member can also	be set to one of the following special
       values defined in  <sys/rtpriocntl.h>,  in  which  case	the  value  of
       rt_tqsecs is ignored:

       RT_TQINF	       Set an infinite time quantum.

       RT_TQDEF	       Set  the	 time quantum to the default for this priority
		       (see rt_dptbl(4)).

       RT_NOCHANGE     Do not set the time quantum. This value is useful  when
		       you  wish  to  change  the  realtime priority of	an LWP
		       without affecting the  time  quantum.  Specifying  this
		       value  when  changing  the  class of an LWP to realtime
		       from some  other	 class	is  equivalent	to  specifying
		       RT_TQDEF.

       When  using  the	 priocntl() PC_SETXPARMS or PC_GETXPARMS commands, the
       first argument after the	command	code must be the class name of the re-
       altime  class  ("RT")  .	 The next arguments are	formed as (key,	value)
       pairs, terminated by a 0	key. The definition for	the keys of the	 real-
       time class can be found in <sys/rtpriocntl.h>. A	repeated specification
       of the same key results in an error return and errno set	to EINVAL.

       +----------------+-------------+-------------------------------+
       |Key		|Value Type   |Description		      |
       +----------------+-------------+-------------------------------+
       |RT_KY_PRI	|pri_t	      |realtime	priority	      |
       +----------------+-------------+-------------------------------+
       |RT_KY_TQSECS	|uint_t	      |seconds in time quantum	      |
       +----------------+-------------+-------------------------------+
       |RT_KY_TQNSECS	|int	      |nanoseconds in time quantum    |
       +----------------+-------------+-------------------------------+
       |RT_KY_TQSIG	|int	      |realtime	time quantum signal   |
       +----------------+-------------+-------------------------------+

       When using the priocntl() PC_GETXPARMS command,	the  value  associated
       with the	key is always a	pointer	to a scheduling	parameter of the value
       type shown in the table above. In contrast, when	using  the  priocntl()
       PC_SETXPARMS  command,  the  scheduling parameter is given as a	direct
       value.

       A priocntl() PC_SETXPARMS command with the class	name ("RT") and	 with-
       out a following (key, value) pair will set or reset all realtime	sched-
       uling parameters	of the target process(es)  to  their  default  values.
       Changing	 the  class of an LWP to realtime from some other class	causes
       the parameters to be set	to their default values. The default  realtime
       priority	 (RT_KY_PRI)  is  0.  A	default	time quantum (RT_TQDEF)	is as-
       signed to each priority class (see rt_dptbl(4)).	The  default  realtime
       time quantum signal (RT_KY_TQSIG) is 0.

       The  value associated with RT_KY_TQSECS is the number of	seconds	in the
       time quantum. The value associated with RT_KY_TQNSECS is	the number  of
       nanoseconds  in	the  quantum.  Specifying  a value of 1,000,000,000 or
       greater for the number of nanoseconds results in	an  error  return  and
       errno is	set to EINVAL. The specified time quantum is rounded up	by the
       system to the next integral multiple of the system clock's  resolution.
       The  maximum  time quantum that can be specified	is implementation-spe-
       cific and equal to INT_MAX ticks, defined in <limits.h>.	 Requesting  a
       quantum	greater	than this maximum results in an	error return and errno
       is  set	to  ERANGE.  If	 seconds  (RT_KY_TQSECS)  but  no  nanoseconds
       (RT_KY_TQNSECS) are supplied, the number	of nanoseconds is set to 0. If
       nanoseconds (RT_KY_TQNSECS) but no seconds (RT_KY_TQSECS) are supplied,
       the   number  of	 seconds is set	to 0. A	time quantum of	0 (seconds and
       nanoseconds are 0) results in an	error return with errno	set to EINVAL.
       Special values for RT_KY_TQSECS are RT_TQINF and	RT_TQDEF (as described
       above). The priocntl() command  PC_SETXPARMS  knows  no	special	 value
       RT_NOCHANGE.

       To change the class of an LWP to	realtime from any other	class, the LWP
       invoking	priocntl() must	have sufficient	privileges. To change the pri-
       ority  or time quantum setting of a realtime LWP, the LWP invoking pri-
       ocntl() must have sufficient privileges or must itself  be  a  realtime
       LWP  whose real or effective user ID matches the	real of	effective user
       ID of the target	LWP.

       The realtime priority and time quantum are inherited across fork(2) and
       the exec	family of functions. When using	the time quantum signal	with a
       user-defined signal handler across the exec functions,  the  new	 image
       must install an appropriate user-defined	signal handler before the time
       quantum expires.	Otherwise, unpredictable behavior might	result.

TIME-SHARING CLASS
       The time-sharing	scheduling policy provides for a  fair	and  effective
       allocation  of the CPU resource among LWPs with varying CPU consumption
       characteristics.	The objectives of the time-sharing policy are to  pro-
       vide good response time to interactive LWPs and good throughput to CPU-
       bound jobs, while providing a degree of user/application	 control  over
       scheduling.

       The  time-sharing  class	has a range of time-sharing user priority (see
       ts_upri below) values that can be assigned to LWPs within the class.  A
       ts_upri	value  of  0  is  defined as the default base priority for the
       time-sharing class. User	priorities range from -x to +x where the value
       of  x is	configurable and can be	determined for a specific installation
       by using	the priocntl() PC_GETCID or PC_GETCLINFO command.

       The purpose of the user priority	is to provide some degree of  user/ap-
       plication  control  over	 the  scheduling  of  LWPs in the time-sharing
       class. Raising or lowering the ts_upri value of an  LWP	in  the	 time-
       sharing	class  raises or lowers	the scheduling priority	of the LWP. It
       is not guaranteed, however, that	an LWP with  a	higher	ts_upri	 value
       will run	before one with	a lower	ts_upri	value, since the ts_upri value
       is just one factor used to determine the	scheduling priority of a time-
       sharing	LWP. The system	can dynamically	adjust the internal scheduling
       priority	of a time-sharing LWP based on other factors  such  as	recent
       CPU usage.

       In addition to the system-wide limits on	user priority (returned	by the
       PC_GETCID and PC_GETCLINFO commands) there is a per LWP	user  priority
       limit  (see ts_uprilim below) specifying	the maximum ts_upri value that
       can be set for a	given LWP. By default, ts_uprilim is 0.

       A tsinfo_t structure with the following members,	defined	in <sys/tspri-
       ocntl.h>,  defines the format used for the attribute data for the time-
       sharing class.

       short	ts_maxupri;	/* Limits of user priority range */

       The priocntl() PC_GETCID	and PC_GETCLINFO commands return  time-sharing
       class attributes	in the pc_clinfo buffer	in this	format.

       The  ts_maxupri	member	specifies the configured maximum user priority
       value for the time-sharing class. If ts_maxupri is x, the  valid	 range
       for both	user priorities	and user priority limits is from -x to +x.

       A   tsparms_t   structure   with	 the  following	 members,  defined  in
       <sys/tspriocntl.h>, defines the format used to specify the time-sharing
       class-specific scheduling parameters of an LWP.

       short	ts_uprilim;	/* Time-Sharing	user priority limit */
       short	ts_upri;	/* Time-Sharing	user priority */

       When  using  the	 priocntl()  PC_SETPARMS  or  PC_GETPARMS commands, if
       pc_cid specifies	the time-sharing class,	the  data  in  the  pc_clparms
       buffer is in this format.

       For  the	 priocntl() PC_GETPARMS	command, if pc_cid specifies the time-
       sharing class and more than one	time-sharing  LWP  is  specified,  the
       scheduling  parameters of the time-sharing LWP with the highest ts_upri
       value among the specified LWPs is returned and the LWP ID of  this  LWP
       is returned by the priocntl() call. If there is more than one LWP shar-
       ing the highest user priority, the one returned	is  implementation-de-
       pendent.

       Any  time-sharing  LWP can lower	its own	ts_uprilim (or that of another
       LWP with	the same user ID). Only	a  time-sharing	 LWP  with  sufficient
       privileges can raise a ts_uprilim. When changing	the class of an	LWP to
       time-sharing from some other class, sufficient privileges are  required
       to set the initial ts_uprilim to	a value	greater	than 0.	Attempts by an
       unprivileged LWP	to raise a ts_uprilim or  set  an  initial  ts_uprilim
       greater than 0 fail with	a return value of -1 and errno set to EPERM.

       Any  time-sharing  LWP  can set its own ts_upri (or that	of another LWP
       with the	same user ID) to any value less	than or	 equal	to  the	 LWP's
       ts_uprilim.  Attempts  to  set the ts_upri above	the ts_uprilim (and/or
       set the ts_uprilim below	the ts_upri) result in the ts_upri  being  set
       equal to	the ts_uprilim.

       Either  of  the ts_uprilim or ts_upri members can be set	to the special
       value TS_NOCHANGE, defined in <sys/tspriocntl.h>, to  set  one  of  the
       values  without	affecting  the	other.	Specifying TS_NOCHANGE for the
       ts_upri when the	ts_uprilim is being set	to a value below  the  current
       ts_upri causes the ts_upri to be	set equal to the ts_uprilim being set.
       Specifying TS_NOCHANGE for a parameter when changing the	 class	of  an
       LWP  to time-sharing (from some other class) causes the parameter to be
       set to a	default	value. The default value for the ts_uprilim is	0  and
       the  default  for the ts_upri is	to set it equal	to the ts_uprilim that
       is being	set.

       When using the priocntl() PC_SETXPARMS or  PC_GETXPARMS	commands,  the
       first  argument	after the command code is the class name of the	 time-
       sharing class ("TS") . The next arguments are formed  as	 (key,	value)
       pairs,  terminated by a 0 key. The definition for the keys of the time-
       sharing class can be found in  <sys/tspriocntl.h>. A repeated  specifi-
       cation of the same key results in an error return and errno set to EIN-
       VAL.

       +----------------+-------------+-------------------------------+
       |Key		|Value Type   |Description		      |
       +----------------+-------------+-------------------------------+
       |TS_KY_UPRILIM	|pri_t	      |user priority limit	      |
       +----------------+-------------+-------------------------------+
       |TS_KY_UPRI	|pri_t	      |user priority		      |
       +----------------+-------------+-------------------------------+

       When using the priocntl() PC_GETXPARMS command,	the  value  associated
       with the	key is always a	pointer	to a scheduling	parameter of the value
       type in the  table  above.  In  contrast,  when	using  the  priocntl()
       PC_SETXPARMS  command,  the  scheduling	parameter is given as a	direct
       value.

       A priocntl() PC_SETXPARMS command with the class	name ("TS") and	 with-
       out  a  following  (key,	value) pair will set or	reset all time-sharing
       scheduling parameters of	the target process(es) to their	 default  val-
       ues. Changing the class of an LWP to time-sharing from some other class
       causes the parameters to	be set to their	default	 values.  The  default
       value  for  the	user  priority limit (TS_KY_UPRILIM) is	0. The default
       value for the user priority (TS_KY_UPRI)	is equal to the	user  priority
       limit (TS_KY_UPRILIM) that is being set.

       The priocntl() command PC_SETXPARMS knows no special value TS_NOCHANGE.

       The  time-sharing  user	priority and user priority limit are inherited
       across fork() and the exec family of functions.

FAIR-SHARE CLASS
       The fair-share scheduling policy	provides a fair	allocation of CPU  re-
       sources	among  projects,  independent  of the number of	processes they
       contain.	Projects are given "shares" to control their quota of CPU  re-
       sources.	See FSS(7) for more information	about how to configure shares.

       The  fair share class supports the notion of per-LWP user priority (see
       fs_upri below) values for compatibility with the	time-sharing  schedul-
       ing class. An fss_upri value of 0 is defined as the default base	prior-
       ity for the fair-share class. User priorities range from	-x to +x where
       the value of x is configurable and can be determined for	a specific in-
       stallation by using the priocntl() PC_GETCID or PC_GETCLINFO command.

       The purpose of the user priority	is to provide some degree of  user/ap-
       plication  control over the scheduling of LWPs in the fair-share	class.
       Raising the fss_upri value of an	LWP in the fair-share class tells  the
       scheduler  to  give  this  LWP more CPU time slices, while lowering the
       fss_upri	value tells the	scheduler to give it less CPU  slices.	It  is
       not  guaranteed,	however, that an LWP with a higher fss_upri value will
       run before one with  a  lower  fss_upri	value.	This  is  because  the
       fss_upri	value is just one factor used to determine the scheduling pri-
       ority of	a fair-share LWP. The system can dynamically adjust the	inter-
       nal scheduling priority of a fair-share LWP based on other factors such
       as recent CPU usage. The	fair-share scheduler attempts  to  provide  an
       evenly graded effect across the whole range of user priority values.

       User  priority  values  do  not interfere with project shares. That is,
       changing	a user priority	value of a process does	not have any effect on
       its  project CPU	entitlement, which is based on the number of shares it
       is allocated in comparison with other projects.

       In addition to the system-wide limits on	user priority (returned	by the
       PC_GETCID  and PC_GETCLINFO commands), there is a per-LWP user priority
       limit (see fs_uprilim below) that specifies the maximum fss_upri	 value
       that can	be set for a given LWP.	By default, fss_uprilim	is 0.

       A   fssinfo_t   structure   with	 the  following	 members,  defined  in
       <sys/fsspriocntl.h>, defines  the format	used for  the  attribute  data
       for the fair-share class.

       short	fss_maxupri;	/* Limits of user priority range */

       The  priocntl()	PC_GETCID  and PC_GETCLINFO commands return fair-share
       class attributes	in the pc_clinfo buffer	in this	format.

       fss_maxupri specifies the configured maximum user  priority  value  for
       the  fair-share	class.	If  fss_maxupri	is x, the valid	range for both
       user priorities and user	priority limits	is from	-x to +x.

       A  fssparms_t  structure	 with  the  following  members,	  defined   in
       <sys/fsspriocntl.h>,  defines the format	used to	specify	the fair-share
       class-specific scheduling parameters of an LWP.

       short	fss_uprilim;   /* Fair-share user priority limit */
       short	fss_upri;      /* Fair-share user priority */

       When using the  priocntl()  PC_SETPARMS	or  PC_GETPARMS	 commands,  if
       pc_cid  specifies the fair-share	class, the data	in the pc_clparms buf-
       fer is in this format.

       For the priocntl() PC_GETPARMS command, if pc_cid specifies  the	 fair-
       share class and more than one fair-share	LWP is specified, the schedul-
       ing parameters of the  fair-share LWP with the  highest	fs_upri	 value
       among  the specified LWPs is returned and the LWP ID of this LWP	is re-
       turned by the priocntl()	call. If there is more than  one  LWP  sharing
       the  highest  user  priority, the one returned is implementation-depen-
       dent.

       Any fair-share LWP can lower its	own fss_uprilim	(or  that  of  another
       LWP with	the same user ID). Only	a fair-share LWP with sufficient priv-
       ileges can raise	an fss_uprilim.	When changing the class	of an  LWP  to
       fair-share from some other class, sufficient privileges are required to
       enter the FSS class or to  set  the  initial  fss_uprilim  to  a	 value
       greater	than 0.	Attempts by an unprivileged LWP	to raise an fs_uprilim
       or set an initial fs_uprilim greater than 0 fail	with a return value of
       -1 and errno set	to EPERM.

       Any  fair-share	LWP  can  set its own fss_upri (or that	of another LWP
       with the	same user ID) to any value less	than or	 equal	to  the	 LWP's
       fss_uprilim. Attempts to	set the	fss_upri above the fss_uprilim (and/or
       set the fss_uprilim below the fss_upri) result in  the  fss_upri	 being
       set equal to the	fss_uprilim.

       Either of the fss_uprilim or fss_upri members can be set	to the special
       value FSS_NOCHANGE (defined in <sys/fsspriocntl.h>) to set one  of  the
       values  without	affecting  the	other. Specifying FSS_NOCHANGE for the
       fss_upri	when the fss_uprilim is	being set to a value below the current
       fss_upri	 causes	 the fss_upri to be set	equal to the fss_uprilim being
       set. Specifying FSS_NOCHANGE for	a parameter when changing the class of
       an LWP to fair-share (from some other class) causes the parameter to be
       set to a	default	value. The default value for the fss_uprilim is	0  and
       the  default  for  the  fss_upri	 is to set it equal to the fss_uprilim
       which is	being set.

       The fair-share user priority and	 user  priority	 limit	are  inherited
       across fork() and the exec family of functions.

FIXED-PRIORITY CLASS
       The  fixed-priority class provides a fixed-priority preemptive schedul-
       ing policy for those LWPs requiring that	the scheduling	priorities  do
       not  get	 dynamically adjusted by the system and	that the user/applica-
       tion have control of the	scheduling priorities.

       The fixed-priority class	has a range of	fixed-priority	user  priority
       (see  fx_upri  below)  values  that  can	be assigned to LWPs within the
       class. A	fx_upri	value of 0 is defined as the default base priority for
       the  fixed-priority  class. User	priorities range from 0	to x where the
       value of	x is configurable and can be determined	for a specific instal-
       lation by using the priocntl() PC_GETCID	or PC_GETCLINFO	command.

       The purpose of the user priority	is to provide user/application control
       over the	scheduling of processes	in the fixed-priority class. For  pro-
       cesses in the fixed-priority class, the fx_upri value is, for all prac-
       tical purposes, equivalent to the scheduling priority of	 the  process.
       The  fx_upri  value  completely determines the scheduling priority of a
       fixed-priority process relative to other	processes  within  its	class.
       Numerically higher fx_upri values represent higher priorities.

       In addition to the system-wide limits on	user priority (returned	by the
       PC_GETCID and PC_GETCLINFO commands), there is a	per-LWP	user  priority
       limit  (see  fx_uprilim below) that specifies the maximum fx_upri value
       that can	be set for a given LWP.	By default, fx_uprilim is 0.

       A structure with	the following member (defined  in  <sys/fxpriocntl.h>)
       defines	the  format used for the attribute data	for the	fixed-priority
       class.

       pri_t   fx_maxupri;	/* Maximum user	priority */

       The priocntl() PC_GETCID	and PC_GETCLINFO commands return  fixed-prior-
       ity class attributes in the pc_clinfo buffer in this format.

       The  fx_maxupri	member	specifies the configured maximum user priority
       value for the fixed-priority class. If fx_maxupri is x, the valid range
       for both	user priorities	and user priority limits is from 0 to x.

       A  structure with the following members (defined	in <sys/fxpriocntl.h>)
       defines the format used to specify  the	fixed-priority	class-specific
       scheduling parameters of	an LWP.

       pri_t	fx_upri;     /*	Fixed-priority user priority */
       pri_t	fx_uprilim;  /*	Fixed-priority user priority limit */
       uint_t	fx_tqsecs;   /*	seconds	in time	quantum	*/
       int	fx_tqnsecs;  /*	additional nanosecs in time quant */

       When  using  the	 priocntl()  PC_SETPARMS  or  PC_GETPARMS commands, if
       pc_cid specifies	the fixed-priority class, the data in  the  pc_clparms
       buffer is in this format.

       For  the	priocntl() PC_GETPARMS command,	if pc_cid specifies the	fixed-
       priority	class and more than one	fixed-priority LWP is  specified,  the
       scheduling  parameters  of  the	fixed-priority	LWP  with  the highest
       fx_upri value among the specified LWPs is returned and the  LWP	ID  of
       this  LWP is returned by	the priocntl() call. If	there is more than one
       LWP sharing the highest user priority, the one returned is  implementa-
       tion-dependent.

       Any fixed-priority LWP can lower	its own	fx_uprilim (or that of another
       LWP with	the same user ID). Only	a fixed-priority LWP  with  sufficient
       privileges can raise a fx_uprilim. When changing	the class of an	LWP to
       fixed-priority from some	other class,  sufficient  privileges  are  re-
       quired  to  set	the  initial fx_uprilim	to a value greater than	0. At-
       tempts by an unprivileged LWP to	raise a	fx_uprilim or set  an  initial
       fx_uprilim  greater than	0 fail with a return value of -1 and errno set
       to EPERM.

       Any fixed-priority LWP can set its own fx_upri (or that of another  LWP
       with  the  same	user  ID) to any value less than or equal to the LWP's
       fx_uprilim. Attempts to set the fx_upri above  the  fx_uprilim  (and/or
       set  the	 fx_uprilim below the fx_upri) result in the fx_upri being set
       equal to	the fx_uprilim.

       Either of the fx_uprilim	or fx_upri members can be set to  the  special
       value  FX_NOCHANGE  (defined  in	 <sys/fxpriocntl.h>) to	set one	of the
       values without affecting	the  other.  Specifying	 FX_NOCHANGE  for  the
       fx_upri	when  the fx_uprilim is	being set to a value below the current
       fx_upri causes the fx_upri to be	set equal to the fx_uprilim being set.
       Specifying  FX_NOCHANGE	for  a parameter when changing the class of an
       LWP to fixed-priority (from some	other class) causes the	 parameter  to
       be  set	to  a default value. The default value for the fx_uprilim is 0
       and the default for the fx_upri is to set it equal  to  the  fx_uprilim
       that  is	 being	set.  The default for time quantum is dependent	on the
       fx_upri and on the system configuration;	see fx_dptbl(4).

       The fx_tqsecs and fx_tqnsecs members are	used for  getting  or  setting
       the  time quantum associated with an LWP	or group of LWPs. fx_tqsecs is
       the number of seconds in	the time quantum and fx_tqnsecs	is the	number
       of   additional	nanoseconds  in	 the  quantum.	For  example,  setting
       fx_tqsecs to 2 and fx_tqnsecs to	500,000,000 (decimal) would result  in
       a  time	quantum	 of  two  and  one-half	seconds. Specifying a value of
       1,000,000,000 or	greater	in the fx_tqnsecs member results in  an	 error
       return  with  errno  set	 to  EINVAL.  Although	the  resolution	of the
       tq_nsecs	member is very fine, the  specified  time  quantum  length  is
       rounded	up  by	the system to the next integral	multiple of the	system
       clock's resolution. The maximum time quantum that can be	 specified  is
       implementation-specific	and  equal  to INT_MAX ticks (defined in <lim-
       its.h>).	Requesting a quantum greater than this maximum results	in  an
       error  return  with errno set to	ERANGE,	although infinite quantums can
       be requested using a special value as  explained	 below.	 Requesting  a
       time  quantum of	0 (setting both	fx_tqsecs and fx_tqnsecs to 0) results
       in an error return with errno set to EINVAL.

       The fx_tqnsecs member can also be set to	one of the  following  special
       values  (defined	 in  <sys/fxpriocntl.h>),  in  which case the value of
       fx_tqsecs is ignored:

       FX_TQINF	       Set an infinite time quantum.

       FX_TQDEF	       Set the time quantum to the default for	this  priority
		       (see fx_dptbl(4)).

       FX_NOCHANGE     Do  not	set  the time quantum. This value is useful in
		       changing	the user priority of an	LWP without  affecting
		       the  time  quantum. Specifying this value when changing
		       the class of an LWP to fixed-priority from  some	 other
		       class is	equivalent to specifying FX_TQDEF.

       When  using  the	 priocntl() PC_SETXPARMS or PC_GETXPARMS commands, the
       first argument after the	command	code must be the  class	 name  of  the
       fixed-priority  class  (FX)  .  The  next arguments are formed as (key,
       value) pairs, terminated	by a 0 key. The	definition for the keys	of the
       fixed-priority  class  can  be  found in	<sys/fxpriocntl.h>. A repeated
       specification of	the same key results in	an error return	and errno  set
       to EINVAL.

       +----------------+-------------+-------------------------------+
       |Key		|Value Type   |Description		      |
       +----------------+-------------+-------------------------------+
       |FX_KY_UPRILIM	|pri_t	      |user priority limit	      |
       +----------------+-------------+-------------------------------+
       |FX_KY_UPRI	|pri_t	      |user priority		      |
       +----------------+-------------+-------------------------------+
       |FX_KY_TQSECS	|uint_t	      |seconds in time quantum	      |
       +----------------+-------------+-------------------------------+
       |FX_KY_TQNSECS	|int	      |nanoseconds in time quantum    |
       +----------------+-------------+-------------------------------+

       When  using  the	 priocntl() PC_GETXPARMS command, the value associated
       with the	key is always a	pointer	to a scheduling	parameter of the value
       type  shown  in the table above.	In contrast, when using	the priocntl()
       PC_SETXPARMS command, the scheduling parameter is  given	 as  a	direct
       value.

       A  priocntl() PC_SETXPARMS command with the class name (FX) and without
       a following (key, value)	pair will set or reset all realtime scheduling
       parameters  of the target process(es) to	their default values. Changing
       the class of an LWP to fixed-priority from some other class causes  the
       parameters to be	set to their default values. The default value for the
       user priority limit (FX_KY_UPRILIM) is 0. The  default  value  for  the
       user  priority  (FX_KY_UPRI)  is	 equal	to  the	 user  priority	 limit
       (FX_KY_UPRILIM) that is being set. A default time quantum (FX_TQDEF) is
       assigned	to each	priority class (see fx_dptbl(4)).

       The  value associated with FX_KY_TQSECS is the number of	seconds	in the
       time quantum. The value associated with FX_KY_TQNSECS is	the number  of
       nanoseconds  in	the  quantum.  Specifying  a value of 1,000,000,000 or
       greater for the number of nanoseconds results in	an  error  return  and
       errno is	set to EINVAL. The specified time quantum is rounded up	by the
       system to the next integral multiple of the system clock's  resolution.
       The  maximum  time quantum that can be specified	is implementation-spe-
       cific and equal to INT_MAX ticks, defined in <limits.h>.	 Requesting  a
       quantum	greater	than this maximum results in an	error return and errno
       is  set	to  ERANGE.  If	 seconds  (FX_KY_TQSECS)  but  no  nanoseconds
       (FX_KY_TQNSECS) are supplied, the number	of nanoseconds is set to 0. If
       nanoseconds (FX_KY_TQNSECS) but no seconds (FX_KY_TQSECS) are supplied,
       the  number  of	seconds	 is set	to 0. A	time quantum of	0 (seconds and
       nanoseconds are 0) results in an	error return with errno	set to EINVAL.
       Special values for FX_KY_TQSECS are FX_TQINF and	FX_TQDEF (as described
       above). The priocntl() command  PC_SETXPARMS  knows  no	special	 value
       FX_NOCHANGE.

       The  fixed-priority user	priority and user priority limit are inherited
       across fork(2) and the exec family of functions.

RETURN VALUES
       Unless otherwise	noted above, priocntl()	returns	0 on success. On fail-
       ure, priocntl() returns -1 and sets errno to indicate the error.

ERRORS
       The priocntl() function will fail if:

       EAGAIN	       An attempt to change the	class of an LWP	failed because
		       of insufficient resources other than memory (for	 exam-
		       ple, class-specific kernel data structures).

       EFAULT	       One of the arguments points to an illegal address.

       EINVAL	       The  argument  cmd was invalid, an invalid or unconfig-
		       ured class was specified,  or  one  of  the  parameters
		       specified was invalid.

       ENOMEM	       An attempt to change the	class of an LWP	failed because
		       of insufficient memory.

       EPERM	       The {PRIV_PROC_PRIOCNTL}	privilege is not  asserted  in
		       the effective set of the	calling	LWP.

		       The  calling LWP	does not have sufficient privileges to
		       affect the target LWP.

       ERANGE	       The requested time quantum is out of range.

       ESRCH	       None of the specified LWPs exist.

SEE ALSO
       priocntl(1), dispadmin(1M), init(1M), exec(2), fork(2), nice(2),	prioc-
       ntlset(2), fx_dptbl(4), process(4), rt_dptbl(4),	privileges(5)

       System Administration Guide: Basic Administration

       Programming Interfaces Guide

SunOS 5.10			  19 Jul 2004			   priocntl(2)

NAME | SYNOPSIS | DESCRIPTION | COMMANDS | REALTIME CLASS | TIME-SHARING CLASS | FAIR-SHARE CLASS | FIXED-PRIORITY CLASS | RETURN VALUES | ERRORS | SEE ALSO

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