[Phase2 RelVal] O(10 million) memory allocations per event by Phase2TrackerMonitorDigi::analyze()

[makortel]

From #45854 (comment)

In Phase2 RelVal Reco job the Phase2TrackerMonitorDigi::analyze() seems to make O(10 million) memory allocations per event. According to the IgProf profile nearly all of these come from MessageLogger.

I see several edm::LogInfo("Phase2TrackerMonitorDigi") << ...; calls there. I guess what happens is that the Phase2TrackerMonitorDigi formats the Info-level messages and injects them into the MessageLogger queue, and MessageLogger then discards the messages because the default logging level is above Info.

I'd suggest to either change the most frequent to LogDebug, in which case the message formatting will be compiled away by default, or change the logging pattern to

edm::LogInfo("Phase2TrackerMonitorDigi").log([&](auto& l) {
  l << ...l;
});

in which case the lambda passed to log() will be called only if the logging level is at least Info (i.e. with the default MessageLogger configuration the lambda will not be called).

[makortel]

assign DQM/SiTrackerPhase2

[makortel]

type performance-improvements

[cmsbuild]

New categories assigned: dqm

@antoniovagnerini,@nothingface0,@rvenditti,@syuvivida,@tjavaid you have been requested to review this Pull request/Issue and eventually sign? Thanks

[cmsbuild]

cms-bot internal usage

[cmsbuild]

A new Issue was created by @makortel.

@Dr15Jones, @antoniovilela, @makortel, @mandrenguyen, @rappoccio, @sextonkennedy, @smuzaffar can you please review it and eventually sign/assign? Thanks.

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[makortel]

assign upgrade

[cmsbuild]

New categories assigned: upgrade

@Moanwar,@srimanob,@subirsarkar you have been requested to review this Pull request/Issue and eventually sign? Thanks

[mmusich]

I'd suggest to either change the most frequent to LogDebug

I think there's no real reason to keep any of the LogInfo-s.
I did that #46575 (among other things)

[makortel]

I did that #46575 (among other things)

The PR was merged, so I think we can close the issue