Switch phase1 tracking to use CA seeding by default

[makortel]

This PR switches the phase1 tracking to use the CA seeding by default (effectively reverting the last commit of #16911). The current default seeding is kept in special workflows (using the same workflow numbers as the special CA workflows had before).

Here are MTV plots comparing CA seeding to the current default with 1000 ttbar+35PU events in 900pre4+#17537+#17511+#17544 (which should correspond to 900pre5 for tracking)
https://mkortela.web.cern.ch/mkortela/tracking/validation/CMSSW_9_0_0_pre4_phase1ca/
Here are also some b tagging performance plots from the same events
https://cms-btag-validation.web.cern.ch/cms-btag-validation/CA-tracking900pre4/plots123/
(thanks to @JyothsnaKomaragiri)

Tested in CMSSW_9_1_X_2017-03-02-2300, expecting changes like above in phase1 workflows, no changes expected in phase0/2.

@rovere @VinInn @felicepantaleo @ebrondol

[makortel]

@cmsbuild, please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/18129/console Started: 2017/03/03 14:34

[cmsbuild]

A new Pull Request was created by @makortel (Matti Kortelainen) for master.

It involves the following packages:

Configuration/Eras
Configuration/PyReleaseValidation
Configuration/StandardSequences

@kpedro88, @fabozzi, @cmsbuild, @franzoni, @GurpreetSinghChahal, @davidlange6 can you please review it and eventually sign? Thanks.
@ghellwig, @felicepantaleo, @GiacomoSguazzoni, @rovere, @VinInn, @Martin-Grunewald, @dgulhan this is something you requested to watch as well.
@Muzaffar, @davidlange6, @smuzaffar you are the release manager for this.

cms-bot commands are listed here #13028

[slava77]

@makortel
please share the DQM*.root files used in the comparisons. (email, maybe)
Thank you.

[kpedro88]

+1

[cmsbuild]

+1
Tested at: deed766
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17766/18129/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17766/18129/summary.html

[fabozzi]

+1

[davidlange6]

assign reconstruction

[cmsbuild]

New categories assigned: reconstruction

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

[slava77]

+1

for #17766 deed766

• configuration changes to switch the default 2017 tracking to use CA, in line with the description
• jenkins tests pass and comparisons with baseline show differences only in 2017/2018 workflows
• supplied plots show improved or consistent behavior
  • MTV plots show roughly the same fake rate, while the efficiency is up significantly at low pt, below 0.3 GeV
  • B-tagging ROC plots show consistent behavior (the previously observed issue with loss of efficiency is gone; IIRC, a part was mitigated directly, a part may have been a fluctuation, and a part is resolved by updates in MVA HP track selections)
• local tests confirm behavior in ttbar PU supplied with the PR; total CPU time in reco is down by ~3.5%

Here are some highlights (baseline = CMSSW_9_1_X_2017-03-09-1100)

the most striking feature is the large increase in tracks with pT below 0.3GeV (plots from TTbar PU35)

this is also visible in pf charged hadrons:

This matches the increase in efficiency at low PT (see supplied MTV plots)
e.g.

and there are no significant indications of fake contribution here at low pt.

The population if short tracks is up quite a bit

The electronMergedSeeds are now mostly 4-hits

========

B-tagging plots in https://cms-btag-validation.web.cern.ch/cms-btag-validation/CA-tracking900pre4/plots123/ look consistent with CA and with the old baseline. This was the main show-stopper in the earlier attempt to switch to CA and it is gone now.

========

Technical performance in 10224:

• CPU time goes down, by about 9% in the iterative tracking modules; the total RECO+miniAOD time is down by about 3.5% (from 16.7 s/evt to 16.1 s/evt)
• (post-event) RSS memory maximum is down by 80MB. This measurement is not particulalry precise, but gives an indication of no increase
• file size on disk increases moderately (miniAOD size up by ~0.8% on 100 events file) driven by increase in low-pt tracks/charged hadrons