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mpss.so.1(1)                     User Commands                    mpss.so.1(1)

       mpss.so.1 - shared object for setting preferred page size


       The  mpss.so.1  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 mpss.so.1, the following
       string needs to be present in the environment  (see  ld.so.1(1))  along
       with  one  or  more MPSS (Multiple Page Size Support) environment vari-


       Once preloaded, the mpss.so.1 shared object reads the  following  envi-
       ronment variables to determine any preferred page size requirements and
       any processes these may be specific to.

       MPSSHEAP=size           MPSSHEAP and MPSSSTACK  specify  the  preferred
       MPSSSTACK=size          page  sizes  for  the  heap  and stack, respec-
                               tively. The specified page size(s) are  applied
                               to all created processes.

                               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-

                               size can be qualified with K, M,  G,  or  T  to
                               specify  Kilobytes,  Megabytes,  Gigabytes,  or
                               Terabytes respectively.

       MPSSCFGFILE=config-file 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 executable. 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

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

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

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

       Example 1: Configuring preferred page sizes using MPSSCFGFILE

       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 configu-
       ration  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=$LD_PRELOAD:mpss.so.1
       example$ 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 configuration file or environment
       variables. Check the error  log  (by  default:  /var/adm/messages)  for

       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

       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=$LD_PRELOAD:mpss.so.1
       example$ MPSSHEAP=512K
       example$ MPSSSTACK=64K
       example$ export LD_PRELOAD MPSSHEAP MPSSSTACK

       Example 3: Precedence rules (continuation from Example 2)

       The preferred page size configuration in MPSSCFGFILE overrides MPSSHEAP
       and MPSSTACK. Appending the following commands 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  applica-
       tions,  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

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

       /etc/mpss.conf                  Configuration file

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

       tab()     allbox;     cw(2.750000i)|    cw(2.750000i)    lw(2.750000i)|
       lw(2.750000i).   ATTRIBUTE  TYPEATTRIBUTE   VALUE   AvailabilitySUNWesu
       (32-bit) SUNWesxu (64-bit) Interface StabilityEvolving

       cat(1),  ld(1),  ld.so.1(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  pre-
       ferred 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 configure the page size
       for descendents based on name matches.

       See also NOTES under ppgsz(1).

SunOS 5.10                        20 Feb 2002                     mpss.so.1(1)