1. BNL / CASPUR / CERN Price/Performance estimates for some compute platforms (AMD, Intel) Pavel Nevski BNL /CERN October 2004

2. P.Nevski - Oct. 2004 - BNL2 Participated : BNL : P.Nevski CASPUR: A.Maslennikov(*), M.Rosati CERN : E.McIntosh, I.McLaren (*) Project Coordinator

3. P.Nevski - Oct. 2004 - BNL3 Goals We have tried to compare the two most interesting platforms of the day: Intel Nocona and AMD Opteron In short, we wanted to check which of the two may deliver more compute power per dollar.

4. P.Nevski - Oct. 2004 - BNL4 Intel Nocona: 2 CPUs at 3.4 GHz, 1GB RAM RedHat Enterprise 3 Kernel: 2.4.21+ Estimated price (*): 3200 Euro (1 GB RAM, incl. IPMI card, rack-mounted) AMD Opteron: 2 CPUs at 2 GHz, 1GB RAM SuSE Enterprise Edition 9.0 Kernel: 2.6.5-7+ SuSE numactl Estimated price (*): 3200 Euro (1 GB RAM, incl. IPMI function, rack-mounted) (*) Prices as calculated by E4 Computer Engineering, Italy Hardware under test (CASPUR)

5. P.Nevski - Oct. 2004 - BNL5 ATLSIM: A full-scale GEANT3 simulation of ATLAS detector (P.Nevski) (typical LHC Higgs events) SixTrack: Tracking of two particles in a 6-dimensional phase space including synchrotron oscillations (F.Schmidt) (http://frs.home.cern.ch/frs/sixtrack.html)http://frs.home.cern.ch/frs/sixtrack.html Sixtrack benchmark code: E.McIntosh (http://frs.home.cern.ch/frs/Benchmark/benchmark.html)http://frs.home.cern.ch/frs/Benchmark/benchmark.html CERN U: Ancient “CERN Units” Benchmark (E.McIntosh) Benchmark suites

6. P.Nevski - Oct. 2004 - BNL6 What was measured On both platforms, we were running one or two simultaneous jobs for each of the benchmarks. On Opteron, we used the SuSE “numactl” interface to make sure that at any time each of the two processors makes use of the right bank of memory. Example of submission, 2 simultaneous jobs: Intel:./TestJob;./TestJob AMD: numactl –cpubind=0 –membind=0./TestJob; numactl –cpubind=1 –membind=1./TestJob

7. P.Nevski - Oct. 2004 - BNL7 Results CERN UnitsSixTrack (seconds/run) ATLSIM (seconds/event) 1 job2 jobs1 job2 jobs1 job2 jobs Intel Nocona 491375,399 185218,218 394484,484 AMD Opteron 528528,528 165165,166 389389,389 While both machines behave in a similar way when only one job is run, the situation changes in a visible manner in the case of two jobs. It may take up to 30% more time to run two simultaneous jobs on Intel, while on AMD there is a notable absence of any visible performance drop.

8. P.Nevski - Oct. 2004 - BNL8 The results we have obtained were predictable. The Intel platform is a plain SMP architecture, and we are observing an apparent contention effect on the memory bus and/or their single memory controller, when running two simultaneous tasks. The new AMD platform implements a scalable NUMA architecture and allows for independent and hence non-interfering CPU-to-memory data exchanges over a pair of memory controllers and Hypertransport buses. As both machines under test cost practically the same, we conclude that going Opteron today may save us up to 30% for the same amount of Teraflops. Conclusions