The vmtune command can be used to modify the VMM parameters that control the behavior of the memory-management subsystem. The option "-p 5" tell the system that if the percentage of real memory occupied by file pages falls below 5%, the page-replacement algorithm steals both file and computational pages, regardless of re-page rates. The default value is around 20%. The option "-P 95" tell the system that if the percentage of real memory occupied by file pages rises above this level, the page-replacement algorithm steals only file pages. The default value is around 80%. The main intent of the page-replacement algorithm is to ensure that computational pages are given fair treatment. The SPINLOOPTIME is a scheduling environment variable which can be used to tune performance. By default, SPINLOOPTIME=40 where 40 is the number of times to retry a busy lock before yielding to another processor.