HP-UX Reference (11i v3 07/02) - 5 Miscellaneous Topics (vol 9)

m
maxtsiz(5) maxtsiz(5)
(Tunable Kernel Parameters)
NAME
maxtsiz, maxtsiz_64bit - maximum size (in bytes) of the text segment for any user process
VALUES
Default
32 bit:
96MB
64 bit: 1GB
Allowed values
32 bit minimum: 0x40000
32 bit maximum: 0x40000000
64 bit minimum: 0x40000
64 bit maximum: 0x3FFFFFFFFFF
DESCRIPTION
User programs on HP-UX systems are composed of five discrete segments of virtual memory: text (or code),
data, stack, shared, and I/O. Each segment occupies an architecturally defined range of the virtual address
space which sets the upper limit to their size. However, text, data and stack segments may have a smaller
maximum enforced via the maxtsiz, maxdsiz and maxssiz tunables.
maxtsiz controls the size of the text segment, which is the read-only executable object code for the pro-
cess that can be shared by multiple processes executing the same program. For example, all copies of vi on
the system use the same text segment.
Who is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect immediately. The size is expected to be a multiple of the base page size.
See the description of _SC_PAGE_SIZE
in getconf(1) for more details. If the value specified is not a mul-
tiple of the base page size, it will be rounded down to the nearest multiple of the base page size.
When Should the Value of This Tunable Be Raised?
maxtsiz should be raised if user processes are receiving the [ENOMEM] error with the following mes-
sage:
exec(2): text exceeds maxtsiz
or
exec(2): text exceeds maxtsiz_64bit
What Are the Side Effects of Raising the Value?
None.
When Should the Value of This Tunable Be Lowered?
This tunable should be lowered to limit the text size of running processes; there is no system performance
reason to do so though.
What Are the Side Effects of Lowering the Value?
None.
What Other Tunable Values Should Be Changed at the Same Time?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parame-
ter values. After installation, some tunable parameters may no longer be at the default or recommended
values. For information about the effects of installation on tunable values, consult the documentation for
the kernel software being installed. For information about optional kernel software that was factory
installed on your system, see HP-UX Release Notes at http://docs.hp.com.
HP-UX 11i Version 3: February 2007 − 1 − Hewlett-Packard Company 267