mpss.so.1(1)
NAME
mpss.so.1 - shared object for setting preferred page size
SYNOPSIS
mpss.so.1
DESCRIPTION
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 variables:
LD_PRELOAD=$LD_PRELOAD:mpss.so.1
ENVIRONMENT VARIABLES
Once preloaded, the mpss.so.1 shared object reads the fol-
lowing environment variables to determine any preferred page
size requirements and any processes these may be specific
to.
MPSSHEAP=size
MPSSSTACK=size
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
processes.
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-
tively.
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 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
exists.
MPSSERRFILE=pathname
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
instead.
EXAMPLES
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 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-
tents.
example$ LD_PRELOAD=$LD_PRELOAD:mpss.so.1
example$ MPSSCFGFILE=mpsscfg
example$ export LD_PRELOAD MPSSCFGFILE
example$ cat $MPSSCFGFILE
foo*:512K:64K
Once the application has been started, pmap (see proc(1))
can be used to view the actual page sizes configured:
example$ 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=$LD_PRELOAD:mpss.so.1
example$ 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 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
ls::
ora* ora1:4m:4m
FILES
/usr/lib/ld/map.bssalign
A template link-editor mapfile for aligning bss (see
NOTES).
/etc/mpss.conf
Configuration file
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWesu (32-bit) |
|_____________________________|_____________________________|
| | SUNWesxu (64-bit) |
|_____________________________|_____________________________|
| Interface Stability | Evolving |
|_____________________________|_____________________________|
SEE ALSO
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)
NOTES
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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