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

Sync reconstruction

• Crash after receiving corrupt TPC data: Fixed. Handling of bad data was actually correct, but multi-threaded pipeline did not handle the error correctly, and the next TF ran into an error.

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.
  • Updated default builds to include A100 GPU architecture, and 75-virtual as lowest computa capability for CUDA JIT compilation, so we should support all CUDA devices from 7.5 onwards now.

GPU ROCm / compiler topics:

• Issues that disappeared but not yet understood: random server reboot with alma 9.4, miscompilation with ROCm 6.2, GPU getting stuck when DMA engine turned off, MI100 stalling with ROCm 5.5.
• 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.
  
• Miscompilation / internal compiler error fixed in new clang for ROCm 7.x, SDMA engine synchronization bug still not fixed.
  • Serialization bug pending.
  • Miscompilation on MI 100 leading to memory error pending. 
  • New miscompilation on MI 50 with ROCm 7.0 when RTC disabled.
  • New miscompilation on MI 50 on ROCm 6.3 and 7.0 when RTC enabled, with latest software. Have a workaround for Pb-Pb data taking, but not compatible to latest tracking developments.
  • Waiting for ROCm 7.2, which could fix the MI100 serialization issue for good. Not clear yet with regards to miscompilation problems.

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.
  
• Waiting for TPC to check PR which uses full cluster errors including average charge and occupancy map errors during seeding.
  
• Final solution: merging transformation maps on the fly into a single flat object:
  • Rebased current PR, CI green now, and gives same results on GPU as on CPU. But result seem wrong, finding 10% less tracks than without the PR.
• 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

Other topics:

EPN GPU Topics:

• AMD nacnot deliver MI210 or newer samples, but Volker has some spare MI210 in Frankfurt, which he can send.
• To be inserted into the EPN farm, together with 1 MI50 and 1 MI100 as second dev-server with EPN setup. (https://its.cern.ch/jira/browse/EPN-572)