NAME - shared object for setting preferred page size



     The shared object provides a means  by  which  the
     preferred  stack  and/or  heap  page size can be selectively
     configured for launched processes and their descendants.  To
     enable,  the following string needs to be present
     in the environment (see along with one  or  more
     MPSS (Multiple Page Size Support) environment variables:



     Once preloaded, the shared object reads  the  fol-
     lowing environment variables to determine any preferred page
     size requirements and any processes these  may  be  specific


           MPSSHEAP and  MPSSSTACK  specify  the  preferred  page
           sizes for the heap and stack, respectively. The speci-
           fied  page  size(s)  are  applied   to   all   created

           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 can be qualified with K, M, G, or  T  to  specify
           Kilobytes,  Megabytes, Gigabytes, or Terabytes respec-

           config-file is a text file which contains one or  more
           mpss configuration entries of the form:

           exec-name exec-args:heap-size:stack-size

           exec-name specifies the name of an application or exe-
           cutable.  The corresponding preferred page size(s) are
           set for newly created processes (see  getexecname(3C))
           that match the first exec-name found in the file.

           exec-name can be a full pathname, a  base  name  or  a
           pattern  string. See File Name Generation in sh(1) for
           a discussion of pattern matching.

           exec-args is an optionally specified pattern string to
           match  against  arguments.  Preferred page size(s) are
           set only if  exec-args  is  not  specified  or  occurs
           within the arguments to exec-name.

           If heap-size and/or stack-size are not specified,  the
           corresponding preferred page size(s) will not be set.

           MPSSCFGFILE  takes  precedence   over   MPSSHEAP   and
           MPSSSTACK. When MPSSCFGFILE is not set, preferred page
           size settings are taken from file /etc/mpss.conf if it

           By default, error messages are logged  via  syslog(3C)
           using   level   LOG_ERR   and  facility  LOG_USER.  If
           MPSSERRFILE  contains  a  valid  pathname   (such   as
           /dev/stderr),  error  messages  will  be  logged there


     Example  1:   Configuring   preferred   page   sizes   using

     The following Bourne shell commands  (see  sh(1))  configure
     the  preferred  page  sizes  to a select set of applications
     with exec names that begin with foo, using  the  MPSSCFGFILE
     environment  variable. The MPSS configuration file, mpsscfg,
     is assumed to have been previously created via a text editor
     like  vi(1). The cat(1) command is only dumping out the con-

     example$ LD_PRELOAD=$
     example$ MPSSCFGFILE=mpsscfg
     example$ export LD_PRELOAD MPSSCFGFILE
     example$ cat $MPSSCFGFILE

     Once the application has been started,  pmap  (see  proc(1))
     can be used to view the actual page sizes configured:

     example$ foobar &
     example$ pmap -s `pgrep foobar`

     If the desired page size is not  configured  (shown  in  the
     pmap output), it may be due to errors in the MPSS configura-
     tion file or environment variables. Check the error log  (by
     default: /var/adm/messages) for errors.

     If no errors can be found, resource or alignment constraints
     may be responsible. See the NOTES section.

     Example 2: Configuring preferred page sizes  using  MPSSHEAP
     and MPSSSTACK

     The following Bourne shell commands configure 512K heap  and
     64K  stack  preferred  page sizes for all applications using
     the MPSSHEAP and MPSSSTACK environment variables.

     example$ LD_PRELOAD=$
     example$ MPSSHEAP=512K
     example$ MPSSSTACK=64K

     Example 3: Precedence rules (continuation from Example 2)

     The preferred page size configuration in  MPSSCFGFILE  over-
     rides  MPSSHEAP  and  MPSSTACK. Appending the following com-
     mands to those in Example 2 would mean that all applications
     will  be  configured  with 512K heap and 64K stack preferred
     page sizes with the exception of those applications, the  ls
     command,  and  all applications beginning with ora that have
     ora1 as an argument, in the configuration file.

     example$ MPSSCFGFILE=mpsscfg2
     example$ export MPSSCFGFILE
     example$ cat $MPSSCFGFILE
     ora* ora1:4m:4m


           A template link-editor mapfile for aligning  bss  (see

           Configuration file


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

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


     cat(1), ld(1),, pagesize(1),  ppgsz(1),  proc(1),
     sh(1), vi(1), exec(2), fork(2), memcntl(2), getexecname(3C),
     getpagesize(3C), syslog(3C), proc(4), attributes(5)


     The heap and stack preferred page  sizes  are  inherited.  A
     child  process  has  the  same  preferred  page sizes as its
     parent. On exec(2), the preferred page sizes are set back to
     the  default  system  page size unless a preferred page size
     has been configured via the mpss shared object.

     ppgsz(1), a proc tool, can also be used to set the preferred
     stack  and/or heap page sizes. It cannot selectively config-
     ure the page size for descendents based on name matches.

     See also NOTES under ppgsz(1).

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