ppgsz - set preferred stack and/or heap page size


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


     The ppgsz utility sets the preferred stack and/or heap  page
     size  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).


     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).

     -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 permitted to set page size.

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

           The heap and stack preferred page sizes are inherited.
           Child  process(es)  created  (see  fork(2))  from  the
           launched process or the target process(es) in the  pid
           list  after ppgsz completes will inherit the preferred
           heap and stack page sizes. The  preferred  page  sizes
           are  set  back  to  the  default  system  page size on
           exec(2) (see getpagesize(3C)).

     -o option[,option]
           The options are:

                 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.

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

     At least one of the above options must be specified.

     size must be a supported page size (see pagesize(1))  or  0,
     in  which  case  the  system will select an appropriate page
     size (see memcntl(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  Kilo-
           bytes,  Megabytes,  Gigabytes,  or  Terabytes, respec-
           tively. 4194304, 0x400000, 4096K, 0x1000K, and 4M  are
           different ways to specify 4 Megabytes.


     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'`


     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 preferred 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.


           Process files.

           A template link-editor mapfile for aligning  bss  (see


     See attributes(5) for descriptions of the  following  attri-

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


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

     Linker and Libraries Guide


     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

     To provide a heap that will be  mapped  with  a  large  page
     size,  an  application  can  be  built  using  a link-editor
     (ld(1))  mapfile  containing  the  bss  segment  declaration
     directive.  Refer  to  the section ``Mapfile Option'' in the
     Linker and Libraries Guide for more details of  this  direc-
     tive     and    the    template    mapfile    provided    in
     /usr/lib/ld/map.bssalign. Users are cautioned that an align-
     ment  specification may be machine-specific 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.

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