April 04, 2017
Earlier this year I pointed you to a method for finding relative performance (rPerf) numbers for your LPAR.
Sometimes you may want to compare the rPerf
of different IBM Power Systems, some of which you may not even have access to. If you're replacing a POWER6 system with POWER8, you'll need some way to compare these systems so, for instance, you'll have a better understanding of the number of cores you'll need to activate for new or existing workloads. As long as you know the model number, the total number of cores on the system and the CPU speed, you can obtain some valuable information.
IBM, which publishes the rPerf values, describes it this way
rPerf estimates are calculated based on systems with the latest levels of AIX and other pertinent software at the time of system announcement. Actual performance will vary based on application and configuration details. The IBM eServer pSeries 640 is the baseline reference system and has a value of 1.0. Although rPerf may be used to compare estimated IBM UNIX commercial processing performance, actual system performance may vary and is dependent upon many factors including system hardware configuration and software design and configuration. Note that the rPerf methodology used for the POWER6 processor-based systems is identical to that used for the POWER5 processor-based systems. Variations in incremental system performance may be observed in commercial workloads due to changes in the underlying system architecture.
You can always find the rPerf numbers by downloading the latest facts and features guides.
Then simply pull those numbers to compare machines. You can also get the IBM Power Systems Performance Report
, which includes other performance values like SPECint and SPECfp. Even better, this handy spreadsheet
has everything in one place.
The spreadsheet includes a regularly updated change log (the latest update is November, and it goes all the way back to 2007) so you can see if the system that you're interested in has been added yet:
Do you use rPerf numbers as you plan for upgrades? Were you aware of these options for getting these values?
Posted April 04, 2017 | Permalink