HP-UX 11i Release Notes (December 2000)

Programming
Libraries
Chapter 13256
turned on usually run faster than with it turned off.
A small block allocator can be turned on through mallopt(); however,
it is not early enough for C++/Java applications. The environment
variable turns it on before the application starts.
mallopt() call can still be used the same way. If the environment
variable is set, and no small block allocator has been used, the
subsequent mallopt() calls can still overwrite whatever is set through
_M_SBA_OPTS. If the environment variable is set, and a small block
allocator has been used, then mallopt() will have no effect. For
example:
$ export _M_SBA_OPTS=512:100:16
where the maxfast size is 512, the number of small blocks is 100, and the
grain size is 16. You must supply all 3 values, and in that order. If not,
the default ones will be used instead.
The _M_ARENA_OPTS and _M_SBA_OPTS environment variables have the
following impact:
• Performance is improved for multi-threaded applications.
• Threaded applications may experience increased heap storage usage
but you can adjust the heap usage through _M_ARENA_OPTS.
NOTE Threaded applications which are linked with archive libc and other
shared libraries where those shared libraries have dependencies on
shared libc may break.
libc Performance Improvements (new)
Overall libc Performance Tuning
This information refers to the system library libc, /usr/lib/libc.sl.
Several header files have been changed as described below. A new
archive library has been added to allow linking the string and memory
routines archived but the application as a whole can be linked shared.
There are now two different 32-bit system libraries. One is built for use
on a PA1.1 machine and the other is built for use on a PA2.0 machine.
The correct library is installed at installation time. Other changes to