Tell ROOT how many thread to use

[Dr15Jones]

PR description:

This is meant to silence a ROOT warning.

PR validation:

All framework related unit test work.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-33038/21337

• This PR adds an extra 20KB to repository

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

  • File FWCore/Services/plugins/InitRootHandlers.cc modified in PR(s): Migrate to tbb::task_group #32804

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for master.

It involves the following packages:

FWCore/Services

@makortel, @smuzaffar, @cmsbuild, @Dr15Jones can you please review it and eventually sign? Thanks.
@makortel, @wddgit 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

[Dr15Jones]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-29c621/13207/summary.html
COMMIT: c8d1782
CMSSW: CMSSW_11_3_X_2021-03-02-1100/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/33038/13207/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 37
• DQMHistoTests: Total histograms compared: 2750983
• DQMHistoTests: Total failures: 5
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2750956
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 36 files compared)
• Checked 156 log files, 37 edm output root files, 37 DQM output files

[makortel]

+1

[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)

[qliphy]

+1