HP-UX 11i June 2001 Release Notes

Process, Threads, Memory, and Kernel Parameters
Kernel Threads vs. CMA Threads (new at 11i original release)
Chapter 8162
Kernel Threads vs. CMA Threads (new at 11i
original release)
The CMA threads (libcma) package, which is POSIX P1003.1a (Draft 4)
compliant, is based on Concert Multi Thread Architecture (CMA). CMA
is a user level threads package in which thread scheduling and
synchronization are handled within the user space without the kernel's
assistance.
CMA threads have been deprecated (slated for future obsolescence) at
HP-UX 11i. This development environment will not be shipped in a
future HP-UX release. Also, there is no plan to release native IA-64 CMA
threads on IA-64 platforms. It is now strongly recommended thatyou use
the currently supported kernel threads libraries and development tools.
Thus, applications using CMA threads should start migrating to kernel
threads.
Multi-threading is also supported in the HP-UX kernel at 11i and is
known as kernel, POSIX or 1x1 threads. This kernel threads
implementation, libpthread, is compliant with the approved POSIX
1003.1c (POSIX.1-1996 Draft 10) standard and will be replacing the
CMA threads package.
The kernel threads implementation allows the application to take
advantage of multiple processors in the system to parallelize execution of
threads.
Compatibility Issues
It is expected that all existing CMA applications will continue to run on
future releases.
As a POSIX standard, the kernel thread implementation facilitates
better application portability on to POSIX-compliant vendor platforms.
CMA applications may have to be ported to HP-UX POSIX threads in
future releases, including those supporting IA-64, as there are
differences in certain API's between CMA threads and HP-UX POSIX
threads.
A white paper Porting DCE Threads Programs to HP-UX 11.0 POSIX
Threads is available to help move from CMA threads to kernel threads
(http://devresource.hp.com/Docs/TechPapers/PortThreads.html).