This script comes to handy when you try to find out the rPerf number of your AIX server:


rperf – rPerf Number Finder

This is a simple Korn shell script finds the Relative Performance rPerf number for the current machine or LPAR from Nigel Griffiths

This is a simple script that outputs the current machine or LPAR to give you the rPerf number.
The rperf numbers are only available for certain number of CPUs.
If you have a different number of CPUs then a rough calculations is made based on the top number of CPUs and dividing appropriately.

If you want to know what rperf used to work out your rating use: rperf -v

There are some problems:

  1. Older machines don’t have rPerf numbers so the script outputs the roltp number. There is no way to convert a roltp number to a rPerf. You will have to apply your own rules for that.
  2. Only certain numbers of CPU have official rPerf Numbers like 4 way, 8 way and 16 way. With LPARs, we can have lots of odd numbers of CPU. In this case, the script guesses the rPerf based on rPerf numbers in a fairly crude way. These are a simple calculation and will not be exact – i.e. it straightens out the SMP curve. The script will give a lower than actual rPerf number.
  3. Shared CPU LPARs that include a faction of a CPU are not handled well – the tool will find the Virtual Processor number and use that as the maximum number of CPUs the LPAR can get.
  4. On shared CPU LPARs the script is not Entitlement aware but entitlement is not a limiting factor on a uncapped LPAR any way. If capped should the script use Entitlement and not VP?
  5. How will the script get updated? – Easy it is a straight forward simple shell script – you can up date it yourself and give the script back to your AIX community – that is what Wiki’s are all about.

Feedback, welcome.

Want more information on rPerf and roltp?

  1. Power Systems (POWER7) rPerfs from
  2. Find out more about rPerf numbers from
  3. The current machines rPerf numbers can be found at
  4. Older machine rPerf numbers can be found at