ITS GPU tracking

• General priorities:
  • Focusing on porting all of what is possible on the device, extending the state of the art, and minimising computing on the host.
  • Optimizations via intelligent scheduling and multi-streaming can happen right after.
  • Kernel-level optimisations to be investigated.
• Tracklet finding: fully ported, PR: https://github.com/AliceO2Group/AliceO2/pull/13737
• TODO:
  
  • Reproducer for HIP bug on multi-threaded track fitting: no progress yet.
  • Move remaining track-finding tricky steps on GPU: started
  • Fix possible execution issues and known discrepancies when using gpu-reco-workflow : no progress yet; will start after the tracklet finding is ported.

DCAFitterGPU

• Deterministic approach via using SMatrixGPU on the host, under particular configuration: no progress yet.