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.
• Test with GPU GRID jobs at NERSC pending.
• 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 and fix crash on RTX Pro 6000.
• Understand deterministic mode issue on NVIDIA Blackwell.

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
• Waiting for TPC to fix bogus TPC transformations for good, then we can revert the workaround.
• Final solution: merging transformation maps on the fly into a single flat object:
  • Maps now yielding correct results, but 1.5x performance regression running on GPUs.
  • Could not find the problem yet (also did not have much time so far). The problem is that I cannot bisect it, since intermediate commits do not run on GPU. Probably have to rewrite the PR and split it in steps that can run on GPU, to see what triggers the slowdown.
• 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
• TPC decoding can now handle data that was encoded with wrong b field, memory scaling factors parameters are configurable as --configKeyValue.

Other topics:

• Need to bump ONNXRuntime to 1.24, Giulio is checking, needed for ROCm 7.2 - Status?
• Status of bumping CMake and boost (https://github.com/alisw/alidist/pull/6135):
  • CI fully green now. Need to check on EPNs, and have to do a special build for anaylzers to check, particular the bump of cgal.
• Test at NERSC still ongoing, all jobs so far failed for non-gpu related reasons (issues with the farm, no free slots for several days, wrong JDL, old JAlien version, ...)

EPN GPU Topics: