Multi-threaded software framework development for the ATLAS experiment

[摘要] ATLAS's current software framework, Gaudi/Athena, has been very successful for the experiment in LHC Runs 1 and 2. However, its single-threaded design has been recognised for some time to be increasingly problematic as CPUs have increased core counts and decreased available memory per core. Even the multi-process version of Athena, AthenaMP, will not scale to the range of architectures we expect to use beyond Run2. ATLAS examined the requirements on an updated multi-threaded framework and laid out plans for a new framework, including better support for High Level Trigger use cases, in 2014. In this paper we report on our progress in developing the new multi-threaded task parallel extension of Athena, AthenaMT. Implementing AthenaMT has required many significant code changes. Progress has been made in updating key concepts of the framework, allowing different levels of thread safety in algorithmic code. Substantial advances have also been made in implementing a data flow centric design, as well as on the development of the new 'event views' infrastructure. These event views support partial event processing and are an essential component to support the High Level Trigger's processing of certain regions of interest. A major effort has also been invested to have an early version of AthenaMT that can run simulation on many core architectures, which has augmented the understanding gained from work on earlier ATLAS demonstrators.

[发布机构] University of Glasgow, University Avenue, Glasgow; G12 8QQ, United Kingdom^1;Rutherford Appleton Laboratory, Harwell, Didcot; OX11 0QX, United Kingdom^2;AGH University of Science and Technology, Krakow; 30-059, Poland^3;Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley; CA; 94720, United States^4;SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, CA; 94025, United States^5;Argonne National Laboratory, 9700 Cass Ave, Lemont; IL; 60439, United States^6;European Organization for Nuclear Research (CERN), Geneva 23; CH-1211, Switzerland^7;Brookhaven National Laboratory, Upton; NY, United States^8;University of Edinburgh, Edinburgh; EH9 3FD, United Kingdom^9

[效力级别] 计算机科学 [学科分类] 计算机科学（综合）

[关键词] ATLAS experiment;Event Processing;High-level triggers;Many-core architecture;Multi-Processes;Multithreaded softwares;Regions of interest;Software frameworks