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ppgsz(1)			 User Commands			      ppgsz(1)

NAME
       ppgsz - set preferred page size for stack, heap,	and/or other anonymous
       segments

SYNOPSIS
       /usr/bin/ppgsz [-F] -o option[,option]  cmd | -p	pid...

DESCRIPTION
       The ppgsz utility sets the preferred page size for stack, heap,	and/or
       other  anonymous	 segments  for	the  target  process(es), that is, the
       launched	cmd or the process(es) in the pid list.	ppgsz stops the	target
       process(es) while changing the page size. See memcntl(2).

OPTIONS
       The following options are supported:

       -F		       Force.  Sets the	preferred page size options(s)
			       for target process(es) even  if	controlled  by
			       other  process(es). Caution should be exercised
			       when using the -F flag. See proc(1).

       -o option[,option]      The options are:

			       heap=size

				   This	option specifies  the  preferred  page
				   size	  for	the   heap   of	  the	target
				   process(es).	heap is	defined	to be the  bss
				   (uninitialized  data) and the brk area that
				   immediately follows the bss	(see  brk(2)).
				   The preferred heap page size	is set for the
				   existing heap and for any  additional  heap
				   memory allocated in the future. See NOTES.

			       stack=size

				   This	 option	 specifies  the	preferred page
				   size	 for   the   stack   of	  the	target
				   process(es).	 The preferred stack page size
				   is set for the existing stack and newly al-
				   located parts of the	stack as it expands.

			       anon=size

				   This	 option	 specifies  the	preferred page
				   size	for all	existing MAP_PRIVATE anonymous
				   segments  of	the target process(es),	 other
				   than	heap and stack,	which are large	enough
				   to  fit  at	least  one aligned page	of the
				   specified size. For the segments  that  are
				   large  enough,  the	preferred page size is
				   set starting	at the first size-aligned  ad-
				   dress  in  the  segment. The	anon preferred
				   pagesize  is	 not  applied  to  MAP_PRIVATE
				   anonymous  segments	created	in the future.
				   See MAP_ANON	in mmap(2).

				   Anonymous  memory  refers  to   MAP_PRIVATE
				   pages that are not directly associated with
				   a file in some filesystem. The  ppgsz  com-
				   mand	 uses  memcntl(2) to set the preferred
				   page	 size  for  anonymous  segments.   See
				   MC_HAT_ADVISE in memcntl(2).

			       At least	one of the above options must be spec-
			       ified.

			       size must be a supported	page size  (see	 page-
			       size(1))	 or  0,	 in which case the system will
			       select an  appropriate  page  size.  See	 memc-
			       ntl(2).

			       size  defaults to bytes and can be specified in
			       octal (0), decimal, or  hexadecimal  (0x).  The
			       numeric value can be qualified with K, M, G, or
			       T to specify Kilobytes,	Megabytes,  Gigabytes,
			       or  Terabytes, respectively. 4194304, 0x400000,
			       4096K, 0x1000K, and 4M are  different  ways  to
			       specify 4 Megabytes.

       -p pid		       Sets  the preferred page	size option(s) for the
			       target process(es) in the process-id (pid) list
			       following  the -p option. The pid list can also
			       consist of names	in the /proc  directory.  Only
			       the  process owner or the super-user is permit-
			       ted to set page size.

			       cmd is interpreted  if  -p  is  not  specified.
			       ppgsz  launches	cmd  and applies page size op-
			       tion(s) to the new process.

			       The heap	and stack preferred page sizes are in-
			       herited.	  Child	  process(es)	created	  (see
			       fork(2))	from the launched process or the  tar-
			       get  process(es)	 in  the  pid list after ppgsz
			       completes will inherit the preferred  heap  and
			       stack  page  sizes. The preferred page sizes of
			       all segments are	set back to the	default	system
			       page size on exec(2) (see getpagesize(3C)). The
			       preferred page size  for	 all  other  anonymous
			       segments	 is  not  inherited by children	of the
			       launched	or target process(es).

EXAMPLES
       Example 1: Setting the preferred	heap and stack page size

       The following example sets the preferred	heap page size to 4M  and  the
       preferred  stack	page size to 512K for all ora--owned processes running
       commands	that begin with	ora:

       example%	ppgsz -o heap=4M,stack=512K -p `pgrep -u ora '^ora'`

       Example 2: Setting the preferred	anonymous page size

       The following example sets the preferred	page size of existing qualify-
       ing anonymous segments to 512k for process ID 953:

       example%	ppgsz -o anon=512k -p 953

EXIT STATUS
       If  cmd	is  specified and successfully invoked (see exec(2)), the exit
       status of ppgsz will be the exit	status of cmd. Otherwise,  ppgsz  will
       exit with one of	the following values:

       0	Successfully  set  preferred page size(s) for processes	in the
		pid list.

       125	An error occurred in ppgsz. Errors include: invalid  argument,
		   invalid  page  size(s)  specified,  and failure to set pre-
		ferred page size(s) for	one or more processes in the pid  list
		or cmd.

       126	cmd was	found but could	not be invoked.

       127	cmd could not be found.

FILES
       /proc/*			       Process files.

       /usr/lib/ld/map.bssalign	       A   template  link-editor  mapfile  for
				       aligning	bss (see NOTES).

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWesu (32-bit)		   |
       +-----------------------------+-----------------------------+
       |			     |SUNWesxu (64-bit)		   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       ld(1), mpss.so.1(1), pagesize(1), pgrep(1), pmap(1),  proc(1),  brk(2),
       exec(2),	  fork(2),   memcntl(2),  mmap(2),  sbrk(2),  getpagesize(3C),
       proc(4),	attributes(5)

       Linker and Libraries Guide

NOTES
       Due to resource constraints, the	setting	of  the	 preferred  page  size
       does not	necessarily guarantee that the target process(es) will get the
       preferred page size. Use	pmap(1)	to view	the actual heap	and stack page
       sizes of	the target process(es) (see pmap -s option).

       Large  pages  are required to be	mapped at addresses that are multiples
       of the size of the large	page. Given that the  heap  is	typically  not
       large  page aligned, the	starting portions of the heap (below the first
       large page aligned address) are mapped  with  the  system  memory  page
       size. See getpagesize(3C).

       To provide a heap that will be mapped with a large page size, an	appli-
       cation can be built using a link-editor (ld(1)) mapfile containing  the
       bss  segment  declaration directive. Refer to the section ``Mapfile Op-
       tion'' in the Linker and	Libraries Guide	for more details of  this  di-
       rective	and the	template mapfile provided in /usr/lib/ld/map.bssalign.
       Users are cautioned that	an alignment specification may be machine-spe-
       cific  and may lose its benefit on different hardware platforms.	A more
       flexible	means of requesting the	most optimal underlying	page size  may
       evolve in future	releases.

       mpss.so.1(1),  a	preloadable shared object, can also be used to set the
       preferred stack and/or heap page	sizes.

SunOS 5.10			  23 Jan 2003			      ppgsz(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | EXIT STATUS | FILES | ATTRIBUTES | SEE ALSO | NOTES

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