GSoC19

My GSoC19 with CERN-HSF AllPix-Squared framework.

During the project, I have implemented the new feature of running the simulation events in parallel. This included:

• Bulding custom run managers for Geant4
• Refactoring Messenger implementation
• Refactoring Event class
• Making almost all modules thread safe
• Adding a buffering mechanism for writer modules

Project Timeline

This is a weekly timeline of my GSoC19 project:

• Week 1 (12-19 May)
  • Setting up the development environment
  • Running initial benchmarks
  • Rebasing previous work
• Week 2 (20-26 May)
  • Studying Geant4 and Allpix codebases
  • Initial attempt for a custom run manager
• Week 3 (27 May-2 June):
  • Studying CMS custom run manager
  • Control seeding of my custom implementation
• Week 4 (3-9 June)
  • Added the custom manager to Allpix
  • Added new finalizeThread() method for modules to cleanup thread-local objects
  • Removed all special handling for Geant4
• Week 5 (10-16 June)
  • Debugging the case where Deposition module doesn't produce output with custom manager
• Week 6 (17-23 June)
  • Fixed the deposition module issues with the new custom manager
• Week 7 (24-30 June)
  • Testing the custom run manager
  • Submitted a merge request to write object ASCII representation used in testing: https://gitlab.cern.ch/allpix-squared/allpix-squared/merge_requests/225
• Week 8 (1-7 July)
  • Investigating how to run the visualization module with the custom manager
• Week 9 (8-14 July)
  • Implemented another run manager for the case of no MT, to use same seeding mechanism.
  • Seperate sensitive detector and field construction in a special class to keep them in deposition module instead of having to move them to geometry construction module
  • LXPLUS disabled on CI
  • Created a different branch for testing with TextWriter module
• Week 10 (15-21 July)
  • Finalized both run managers implementation
  • Debugging with Heligring to catch any errors
  • Fix the case of using ION tables
  • Conduct testing plan to test both MT and non-MT run manager and make sure they produce same output given same seed
  • Refactored messenger and event classes
• Week 11 (22-28 July)
  • Running benchmarks with the custom managers
  • Identified the ROOT issue and identified the problamatic version
  • Using same ROOT as CI
  • Fixed various issues after running on CentOS instead of Ubuntu
• Week 12 (29 July - 4 August)
  • Fixed the slowdown on single core issue
  • Opened merge request
  • Fixing code review issues
  • Implementing buffering for each specific module
• Week 13 (4-11 August)
  • Abandon iintial buffering approach
  • Fixing code review comments
  • Running benchmarks and tests
• Week 14 (12-18 August)
  • Updating documentation and user manual
  • Fixing code review comments
  • Running vTune profiler and analyzing performance, and hotspots
  • Running final benchmarks
• Week 15 (19- August)
  • Running final testing using MT On and Off
  • Fixed an issue with UI macros in the MT run manager