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Estimate rperf for your LPAR

January 03, 2017

A recent Nigel Griffiths tweet highlighted this page:

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:
* 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.
* 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.
* 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.
* 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?

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 via the comments below.

By definition: The rPerf number is the Relative Performance number when compared to the above RS/6000 44p Model 270 374 MHz announced on 7th February 2000, which has a rPerf of exactly 1.

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.

rperf script wiki page
https://www.ibm.com/developerworks/community/wikis/home#!/wiki/Power%20Systems/page/rperf

e-mail to XXXX@uk.ibm.com

Got a machine that is not on the list or any other problem ?
Make sure you have the latest rperf version
Run: rperf -v
Capture the output
Add that output as a comment at the bottom of this webpage
I get automatically notified and will sort it out
If you are a proper Techie: work out the missing line and put that in the comment too.
Thanks for your use, help and feedback, Nigel Griffiths

There are links for downloading the files. As of this writing, rperf_v33 is the most recent, from November.

Posted January 03, 2017 | Permalink

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