AIX Settings
You should consider the values of the AIX settings listed in this section.
- LDR_CNTRL=USERREGS Specifying the USERREGS option tells the system to save all general-purpose user registers across system calls made by an application. This can be helpful in applications doing garbage collection. See:
- AIXTHREAD_SCOPE=S Choose to use a different thread model. Setting the environment variable AIXTHREAD_SCOPE=S for that process, we can set the thread model to 1:1. See:
http://swervedba.wordpress.com/2011/05/14/importance-of-aixthread_scope-in-oracle-3/
- AIXTHREAD_MUTEX_DEBUG=OFF Maintains a list of active mutexes for use by the debugger. If the program contains a large number of active mutexes and frequently creates and destroys mutexes, this might create higher overhead for maintaining the list of mutexes. Leaving the variable set to OFF disables the list. See:
- AIXTHREAD_RWLOCK_DEBUG=OFF Maintains a list of read-write locks for use by the debugger. If the program contains a large number of active read-write locks and frequently creates and destroys read-write locks, this might create higher overhead for maintaining the list of read-write locks. Setting the variable to OFF will disable the list. See:
- AIXTHREAD_COND_DEBUG=OFF Maintains a list of condition variables for use by the debugger. If the program contains a large number of active condition variables and frequently creates and destroys condition variables, this might create higher overhead for maintaining the list of condition variables. Setting the variable to OFF disables the list. See:
- sedmgr -c exempt tibamx_BPMNode-INT (64-bit only) Exempts the process from the Stack Execution Disable (SED) mechanism. The SED facility is available only in the AIX 64-bit kernel operating systems. See:
http://www-03.ibm.com/systems/power/software/aix/security/feature/sed.html
http://pic.dhe.ibm.com/infocenter/aix/v6r1/topic/com.ibm.aix.cmds/doc/aixcmds5/sedmgr.htm
- SPINLOOPTIME=128 Controls the number of times to retry a busy lock before yielding to another processor (only for libpthreads). The default is 40. If threads are going to sleep often (lot of idle time), then the SPINLOOPTIME value might not be high enough.
- YIELDLOOPTIME=32 Controls the number of times to yield the processor before blocking on a busy lock (only for libpthreads). The processor is yielded to another kernel thread, assuming there is another runnable kernel thread with sufficient priority. If threads are going to sleep often (lot of idle time), then the YIELDLOOPTIME might not be high enough.
- AIXTHREAD_MUTEX_FAST=ON Enables the use of the optimized mutex locking mechanism. If the program experiences performance degradation due to heavy mutex contention, then setting this variable to ON will force the pthread library to use an optimized mutex locking mechanism that works only on process private mutexes.
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