Specifications Platform OS CPU #Cores MacBook Air OS X 10.9.2 - PowerPoint PPT Presentation

Specifications Platform OS CPU #Cores MacBook Air OS X 10.9.2 1.7 GHz Intel Core i7 2 Linux Desktop Ubuntu 13.10 3.4 GHz Intel Core i7 4 Titan Cray Linux 16 2.2GHz AMD Opteron 6274 (Interlagos) Supada (ORNL) Geant4 Multithreading April 16, 2014 1 / 5

Case Study Basic Geant4 example B2a 10,000 events Supada (ORNL) Geant4 Multithreading April 16, 2014 2 / 5

Execution Time 120 MacBook Air Linux Desktop Execution Time (seconds) 100 Titan 80 60 40 20 0 1 2 4 8 16 Number of Threads Supada (ORNL) Geant4 Multithreading April 16, 2014 3 / 5

Speedup in Theory S p = T 1 T p T 1 = execution time on one thread T p = execution time on p threads Ideally: T p = T 1 = ⇒ S p = p p Reality: T p = T 1 p + T c = ⇒ S p < p , where T c is the communcation time among threads Supada (ORNL) Geant4 Multithreading April 16, 2014 4 / 5

Speedup MacBook Air 6 Linux Desktop Titan Speedup 4 2 0 1 2 4 8 16 Number of Threads Supada (ORNL) Geant4 Multithreading April 16, 2014 5 / 5