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Get a rPerf performance rating for your AIX LPAR

How To


Summary

Run this script of your AIX server to calculate an estimated rPerf rating for that particular Logical Partition (LPAR) also called virtual machine (VM). The estimate is based on the number CPUs and Machine-Type-Model (MTM) calculated from the official documented rPerf ratings.

Objective

Nigels Banner
Use the rperf script for:
  1. Adjusting the size of an LPAR or VM.
  2. Sizing a new POWER server
  3. Planning server consolidation
  4. Moving workloads with Live Partition Mobility
These actions may, need a rating the computer power of your current LPAR or VM. This script does that. Then, you can map the required total rPerf on to a new server. When you estimate the rPerf value for an alternative server, the article Sizing with rperf - Don't Forget the Assumptions is recommended.
RS600 Model 44p-270
By definition: The rPerf number is the Relative Performance number when compared to the pictured RS/6000 44p Model 270 374 MHz which IBM announced on 7 February 2000, which has a rPerf of exactly 1.0.

Environment

An AIX Logical Partition (virtual machine), login username, password, and this Korn script.

Steps

This simple Korn shell script, by Nigel Griffiths, finds the Relative Performance rPerf number for the current machine or LPAR. The official rPerf numbers are only available for certain numbers of CPUs. If you have a different number of CPUs, then a rough calculation is made based on the next largest official rating and dividing that ratio.

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

There are some example problems you might encounter:

  1. Older servers 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 have to apply your own rules for that rating system.
  2. Only certain numbers of CPUs 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. This method is a simple calculation and might not be exact, as it straightens out the SMP curve. The script gives a number less than actual rPerf number.
  3. Shared CPU LPARs that include a faction of a CPU are not handled well - the tool finds 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 an uncapped LPAR any way. If capped, perhaps the script might use Entitlement and not VP?
  5. How does 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 by email (details at the end).

Syntax by example:

Assuming you rename the script to just rperf and have it in your $PATH

blue:nag:/home/nag/rperf $ rperf -?
Usage: .
./rperf [-vehH]

blue:nag:/home/nag/rperf $ rperf
82.77 rPerf estimated based on 8.00 Virtual CPU cores

blue:nag:/home/nag/rperf $ rperf -e
82.77 rPerf estimated based on 8.00 Virtual CPU cores
41.38 rPerf estimated based on 4.00 Uncapped Entitlement CPU cores

blue:nag:/home/nag/rperf $ rperf -h
blue 82.77 rPerf estimated based on 8.00 Virtual CPU cores

blue:nag:/home/nag/rperf $ rperf -h -e
blue 82.77 rPerf estimated based on 8.00 Virtual CPU cores
blue 41.38 rPerf estimated based on 4.00 Uncapped Entitlement CPU cores

blue:nag:/home/nag/rperf $ rperf -v
Information is from public documents from www.ibm.com
-- - System p Performance Report
-- - System p Facts and Features Document
-- - Power Systems Facts and Features Document
-- - rperf script Version:31 Date:18thJune2015
Machine=IBM,8233-E8B MHz=3550 Rounded-MHz=3550 CPUs=8 CPUType=PowerPC_POWER7
lookup IBM,8233-E8B_3550_8
matchup 32 331.06
calculate cpus=8 from 32 331.06
82.77 rPerf estimated based on 8.00 Virtual CPU cores
41.38 rPerf estimated based on 4.00 Uncapped Entitlement CPU cores
blue:nag:/home/nag/rperf $ rperf -H
rperf -v -e -h -H
  -v = verbose mode and Entitlement (-e)
  -e = output Entitlement rating and Capped / Uncapped state (in addition)
  -h = output the short hostname at the start of the line
  -H = Help = this output

rperf outputs the performance number of the current machine or LPAR
either Relative Performance (rPerf) or Relative OLTP (roltp)
Depending on the age of the machine.
There is no simple way to convert from roltp to rPerf - sorry.

If it says estimated then it is NOT an official number.
For LPARs the number may be estimated but it is a simple maths calculation
i.e. if we have the official number for 4 CPUs then a 1 CPU LPAR is simply
a fourth - this will be an under estimate.

Got a machine that is not on the list or any other problem ?
  1. Make sure you have the latest rperf version
  2. Run: rperf -v
  3. Capture the output
  4. E-Mail me this information - see the Additional Information section for details
  5. If you are a Techie: work out the missing line, test, and send them too
  6. Thanks for using rperf and feedback

Want more information on rPerf?

  1. Power Systems POWER7 to Power10 rPerfs can be found in the Power Performance Report here: 
  2. Older machine rPerf numbers back to POWER5 can be found in the Archive Power Performance Report here

Current Release for Download - click the file name for the download:

This download file is a ksh shell script - make it executable (chmod ugo+x rperf) and run it (./rperf):
  •   rperf_v41_1.zip - Version 41 - July 2022
    • Supporting the new Power10 E1050 server and the Power10 Scale-our servers: S1024, S1014, S1022, and S1022s.
    • Unzip The file - it was required by this hosting website.
    • Note This version needs to be checked for the new Power10 servers.
      email the output from rperf -v to Nigel Griffiths nag@uk.ibm.com
  •  rperf_v40.zip - Version 40 - Dec 2021
    • Supporting the Power10 E1080 server.
    • Unzip The file - it was required by this hosting website.
  • rperf_v38 - Version 38 - July 2020
    • Previously added S922 +S924 with 11 & 22 core models
    • S914 few percent higher rating
    • New G models with all PCIe slots are Gen4, new front bay NVME disk options, and Power Enterprise Pool 2.0 PEP2.0 (pooling of CPU only paid for by the minute)
  • rperf_v37 - Version 37 - Sept 2018
    • Added POWER9 Enterprise E950 and E980

Debug or Experiments or "What if" Questions

$ export LOOKUP=IBM,9119-FHB_4000_256
$ export CPUS=250
$
$ rperf -v 
rperf Debug mode using your shell variable LOOKUP
LOOKUP=IBM,9119-FHB_4000_256
rperf Debug mode using your shell variable CPUS
CPUS=250
Information is from public documents from www.ibm.com
-- - System p Performance Report
-- - System p Facts and Features Document
-- - Power Systems Facts and Features Document
lookup IBM,9119-FHB_4000_256
matchup 32 372.27 256 2978.16
calculate cpus=250 from 32 372.27
calculate cpus=250 from 256 2978.16
2908.36 rPerf estimated
$
But what I actually have on this server is:
$ rperf -v
Information is from public documents from www.ibm.com
-- - System p Performance Report
-- - System p Facts and Features Document
-- - Power Systems Facts and Features Document
Machine=IBM,9117-MMA MHz=4704 Rounded-MHz=4700 CPUs=3 CPUType=PowerPC_POWER6
lookup IBM,9117-MMA_4700_3
matchup 2 20.13 4 40.26 8 74.89 12 105.89 16 134.35
calculate cpus=3 from 2 20.13
calculate cpus=3 from 4 40.26
30.20 rPerf estimated
$

Additional Information

If you find errors or missing Power servers or models, then email me: 

  • Subject: rperf
  • Email: nag@uk.ibm.com  

Document Location

Worldwide

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Document Information

Modified date:
20 July 2022

UID

ibm11110465