PixelTracksAlpaka CMSSW Fork setup

pixel_local_reconstruction_setup.md

PixelTracksAlpaka CMSSW Fork setup

❗ This guide will become obsolete very soon!

Introduction

During the 11th Patatrack Hackathon, the PixelTracksAlpaka CMSSW fork was created in order to pool the changes towards the final porting of Pixel-local GPU reconstruction from CUDA to Alpaka.

As of writing, the fork is based on CMSSW_12_6_X_2022-11-28-2300.

There are currently two separate efforts:

• Porting the Digis, Clusters and RecHits formats to Eric's SoA. PR here.
• Porting the Tracks and TrajectoryState formats to Eric's SoA. PR here.

A presentation of the SoA Templates used can be found here.

Prerequisites

• A CMS online account. This is different to an LXPLUS account. See here for instructions.

Setup

Clone the appropriate CMSSW version

• Login to a CMS Online machine (instructions here). From within an LXPLUS machine:

  • ssh -f -N -D18080 cmsusr.cern.ch
    ssh -o ProxyCommand='nc --proxy localhost:18080 --proxy-type socks5 %h %p' gpu-c2a02-39-01.cms

  • You can change gpu-c2a02-39-01.cms to any other machine found in the list of the document linked above.
• Setup your machine:

  • export SCRAM_ARCH=el8_amd64_gcc10
    source /cvmfs/cms.cern.ch/cmsset_default.sh
    export VO_CMS_SW_DIR=/cvmfs/cms.cern.ch/

• Configure GitHub access: instructions here.
• Clone CMSSW:

  • cmsrel CMSSW_12_6_X_2022-11-28-2300
    cd CMSSW_12_6_X_2022-11-28-2300/src
    cmsenv
    git cms-init

• Verify this can be built without errors:
  • scram b -j 8

Pulling changes from a PixelTracksAlpaka PR

• Choose an open PR, e.g.: PixelTracksAlpaka/cmssw#2
• On your CMS online machine:
  • Checkout the required packages for the specific PR:

    git cms-addpkg CUDADataFormats/SiPixelCluster CUDADataFormats/SiPixelDigi CUDADataFormats/TrackingRecHit DataFormats/Portable EventFilter/SiPixelRawToDigi HeterogeneousCore/CUDAServices HeterogeneousCore/CUDAUtilities RecoLocalTracker/SiPixelClusterizer RecoLocalTracker/SiPixelRecHits
    git cms-checkdeps -a -A

  • Pull the changes:

    cd CMSSW_12_6_X_2022-11-28-2300/src
    cmsenv
    git apply https://github.com/PixelTracksAlpaka/cmssw/pull/2.patch  # We simply add ".patch" at the end of the URL

Validation

Once changes have been made to the source code and the code compiles succesfully, you can validate its outputs by running an appropriate workflow:

• Run runTheMatrix.py:

  runTheMatrix.py -w upgrade -l 11634.502 -t 8

• Change the generated cmdLog file for GENSIM step to have 100 files for validation.
• Execute:

  . cmdLog

• Run the validation:

  harvestTrackValidationPlots.py step3_inDQM*.root -o file.root
  makeTrackValidationPlots.py file.root

Contributing to the PixelTracksAlpaka fork

• Create a cmssw fork to your personal GitHub account. You could also create a PixelTracksAlpaka fork.
• On your CMS online machine:

  • git remote remove my-csmssw
    git remote add my-cmssw https://github.com/<your-github-username>/cmssw.git  # If using git over HTTPS
    git fetch my-cmssw

• You can now push to any branch you create on your personal fork. Once a branch is created, you can make a PR to the PixelTracksAlpaka/cmssw fork.