FAQ HEP SPEC06
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TRANSITION TO HEP SPEC, A NEW CPU BENCHMARK
The traditional si2k CPU benchamark is now obsolete and it is time to move to HEP SPEC, a new CPU benchmark that will replace si2k and will become the reference benchmark for accounting purposes.
Details
The *HEP-SPEC06* benchmarck is designed to scale with the performances of the high-energy physics codes on similar machines. The goal was to have an accuracy of ± 5% but for the moment the agreement is significantly higher
Have a look at the "Transition to a new CPU benchmarking unit for the WLCG" for a detailed description of “why".
The measurement of HEP-SPEC repeated on identical machines varies less than 1%. If the computing machines are similar, i.e. same processors and at least 2GB per core, the results obtained are very close, within some percent, so that it is unnecessary to perform measures on all computing hosts. It is enough to do the measurement for one type of processor and consider it valid for all the machines with the same processor.
If you are using different OS and specially different compilers, the data will change.
Some example results are available on the HEPIX group-page at CASPUR: HEPIX Bench-Results, where one can see the differences between tra gcc3.4.x e gcc4.1.x. Other results - available on the wiki-page HEPIX - CASPUR
An interesting table with already calculated values, that you may use, is available on the INFN-CCR Server working group:
http://www.infn.it/CCR/server/
Other important results computed by INFN-T1 site-admins are available at the following link:
http://tier1.cnaf.infn.it/monitor/SPEC/
More HEP SPEC Benchamark results from GRIDPP here.