Open issues regarding the ECAL local reconstruction on GPU

[fwyzard]

Open issues regarding the ECAL local reconstruction on GPU

• Update the ECAL ESProducts and move them to a more correct place
• Migrate GPU code to use common constants and functions
• Add references for magic numbers

[fwyzard]

Update the ECAL ESProducts and move them to a more correct place

Make the equivalent changes regarding to the conditions that were done for HCAL in #32039.

Move the conditions types used on the GPU from

• EventFilter/EcalRawToDigi/interface/ElectronicsMappingGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalGainRatiosGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalIntercalibConstantsGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalLaserAPDPNRatiosGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalLaserAPDPNRatiosRefGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalLaserAlphasGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalLinearCorrectionsGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalMultifitParametersGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalPedestalsGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalPulseCovariancesGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalPulseShapesGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalRecHitParametersGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalRechitADCToGeVConstantGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalRechitChannelStatusGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalSamplesCorrelationGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalTimeBiasCorrectionsGPU.h
• RecoLocalCalo/EcalRecAlgos/interface/EcalTimeCalibConstantsGPU.h

and the corresponding .cc files to CondFormats/EcalObjects/

Update them to use

• edm::propagate_const_array<cms::cuda::device::unique_ptr<float[]>> instead of float *
• cms::cuda::make_device_unique<float[]> instead of cudaMalloc
• cms::cuda::copyAsync instead of cudaMemcpyAsync

[fwyzard]

Migrate GPU code to use common constants and functions

The functions in RecoLocalCalo/EcalRecProducers/plugins/Common.h are only used by the GPU implementation.

They could be reused from DataFormats/EcalDigi/interface/EcalMGPASample.h.

[cmsbuild]

A new Issue was created by @fwyzard Andrea Bocci.

@Dr15Jones, @dpiparo, @silviodonato, @smuzaffar, @makortel, @qliphy can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[fwyzard]

assign reconstruction

[fwyzard]

assign heterogeneous

[cmsbuild]

New categories assigned: heterogeneous,reconstruction

@slava77,@perrotta,@makortel,@jpata,@fwyzard you have been requested to review this Pull request/Issue and eventually sign? Thanks

[fwyzard]

@thomreis FYI

[fwyzard]

Add references for magic numbers

RecoLocalCalo/EcalRecProducers/plugins/EcalMultifitParametersGPUESProducer.cc uses variois hard-coded numbers without a clear explanation of their origin.
They appear to be reused in the same way in

RecoLocalCalo/EcalRecProducers/plugins/EcalUncalibRecHitWorkerMultiFit.cc
RecoLocalCalo/EcalRecProducers/plugins/EcalUncalibRecHitWorkerRatio.cc
RecoLocalCalo/EcalRecProducers/plugins/EcalUncalibRecHitWorkerGlobal.cc

The original CPU code should be updated (for example, moving those numbers to a central place and adding comments to explain their source) and the GPU code should then be updated accordingly.

[jpata]

Taking note of a few more specific todos:

• EventFilter/EcalRawToDigi/plugins/EcalRawToDigiGPU.cc: esConsumes and constants
• RecoLocalCalo/EcalRecProducers/plugins/EcalRecHitBuilderKernels.cu: very long function, many short variable names with a long lifetime (t_i, t_f, t1, t2 etc), several unaddressed TODO comments in the code like "how the heck is this possible", "Please clean up the code, ... also the original one!" etc
• RecoLocalCalo/EcalRecProducers/plugins/EcalRecHitProducerGPU.cc: might not have to be edm::ExternalWork, https://github.com/cms-sw/cmssw/pull/31719/files#r511164561
• RecoLocalCalo/EcalRecProducers/plugins/KernelHelpers.cu: some hardcoded constants, comments like "why on hell things are so complex and not simple" to be removed
• RecoLocalCalo/EcalRecProducers/plugins/TimeComputationKernels.cu: hardcoded constants
• RecoLocalCalo/EcalRecProducers/python/ecalRecHitGPU_cfi.py: TODOs in the code with unclear status
• CPU to GPU workflow comparisons do not produce equivalent results, Patatrack integration - ECAL local reconstruction (7/N) #31719 (comment)