Environment variables for performance tuning

Environment Variables Description External Documentation

LDR_CNTRL

You can use the LDR_CNTRL environment variable to configure an application to use large pages for the application's data and heap segments. Setting an environment variable to request large pages

MALLOCALIGN
MALLOCTYPE
MALLOCOPTIONS
MALLOCDEBUG

These variables allow you to specify the memory allocation policy. System Memory Allocation Using the malloc Subsystem

MALLOCBUCKETS
MALLOCMULTIHEAP
AIXTHREAD_AFFINITY
AIXTHREAD_COND_DEBUG
AIXTHREAD_ENRUSG
AIXTHREAD_MNRATIO
AIXTHREAD_MUTEX_DEBUG
AIXTHREAD_MUTEX_FAST
AIXTHREAD_PREALLOC
AIXTHREAD_RWLOCK_DEBUG
AIXTHREAD_SCOPE
AIXTHREAD_SUSPENDIBLE
SPINLOOPTIME
YIELDLOOPTIME

Within the libpthreads.a framework, a series of tuning knobs have been provided that might impact the performance of the application. Thread environment variables

MEMORY_AFFINITY

Allows you to configure the placement of user memory. Memory placement with the MEMORY_AFFINITY environment variable

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