Color code: (critical, news from this week: blue, news from last week: purple, no news: black)

Sync reconstruction

Async reconstruction

• Need to investigate short GPU stall problem.
• Limiting factor for pp workflow is now the TPC time series, which is to slow and creates backpressure (costs ~20% performance on EPNs). Enabled multi-threading as recommended by Matthias - need to check if it works.
• Will tune existing 16-core settings, add a SITEARCH for 16core CPU, and 16coreCPU + generic NVIDIA / AMD GPU, like for 8 core.
• Will retune EPN async workflow for TPC + ITS on GPU on 2025 data.

GPU ROCm / compiler topics:

• Problem with building ONNXRuntime with MigraphX support.
• Need to find a way to build ONNXRuntime with support for CUDA and for ROCm.
• Try to find a better solution for the problem with __device__ inline functions leaking symbols in the host code.
  
• Need to check ROCm 7.2 corrtecness.
• Need to understand deterministic mode issue on AMD Pro 9700 reported by Oliver - Status?

TPC / GPU Processing 

• WIP: Use alignas() or find a better solution to fix alignment of monte carlo labels: https://its.cern.ch/jira/browse/O2-5314
• Need to check the problem with ONNX external memory allocator.
• Next high priority topic: Improvements for cluster sharing and cluster attachment at lower TPC pad rows. PR: https://github.com/AliceO2Group/AliceO2/pull/14542
• Check for unnecessary f64 instructions in GPU code.

Other topics:

• Need to bump ONNXRuntime to 1.24, Giulio is checking, needed for ROCm 7.2 - Status?
• Test at NERSC successfull, first results presented at CHEP and LHCP.
  • GPU TPC + ITS tracking working nicely on A100 GPU, no backpressure from GPU, but workflow is CPU-bound, as on EPNs.
  • For some reasons, the GPUs at NERSC perform much slower than on EPNs (even though both are 64 cores), should be investigated.

EPN GPU Topics: