phase-2 reco CPU hotspot: PFElecTkProducer

[guitargeek]

PR description:

Speed up of another electron related Phase II bottleneck, reported in #30953:

• precompute track eta and phi with edm::soa::EtaPhiTable
• skip expensive computation of number of shared hits if track lies outside of matching cone
• as consequence, cost of PFElecTkProducer::FindPfRef in workflow 23434.21 (step3) drops from 2.5 % to 0.01 % (see this report)

PR validation:

CMSSW compiles and local matrix tests pass, plus profiling.

if this PR is a backport please specify the original PR and why you need to backport that PR:

No backport intended.

[cmsbuild]

The code-checks are being triggered in jenkins.

[hatakeyamak]

@hatakeyamak @bendavid
Thanks @guitargeek

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-30992/17442

• This PR adds an extra 24KB to repository

• There are other open Pull requests which might conflict with changes you have proposed:

  • File RecoParticleFlow/PFTracking/plugins/PFElecTkProducer.cc modified in PR(s): phase-2 reco CPU hotspot: egammaTools::getConversionInfos #30956

[cmsbuild]

A new Pull Request was created by @guitargeek (Jonas Rembser) for master.

It involves the following packages:

DataFormats/ParticleFlowReco
RecoParticleFlow/PFTracking

@perrotta, @jpata, @cmsbuild, @slava77 can you please review it and eventually sign? Thanks.
@mmarionncern, @makortel, @cbernet, @rovere, @lgray, @lecriste, @hatakeyamak, @seemasharmafnal this is something you requested to watch as well.
@silviodonato, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[kpedro88]

please test

[cmsbuild]

The tests are being triggered in jenkins.

• CMSSW_11_2_X_2020-07-30-1100/slc7_amd64_gcc820: https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/8445/console Started: 2020/07/30 22:22

[cmsbuild]

+1
Tested at: 1bb3352
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-a911fc/8445/summary.html
CMSSW: CMSSW_11_2_X_2020-07-30-1100
SCRAM_ARCH: slc7_amd64_gcc820

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-a911fc/8445/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 34
• DQMHistoTests: Total histograms compared: 2525444
• DQMHistoTests: Total failures: 7
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2525390
• DQMHistoTests: Total skipped: 47
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 33 files compared)
• Checked 144 log files, 17 edm output root files, 34 DQM output files

[jpata]

+1

• tests pass with no reco difference
• PR implements technical changes to the PFElecTkProducer::findPfRef
• significantly reduces the CPU cost of the module in question

Thank you @guitargeek, this is great. My only comment is that I see this code is still using old-style getByHandle, this can be followed up separately in a refactoring.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @silviodonato, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[silviodonato]

+1