cms-sw/cmssw — pull request #4924 by mark-grimes (2014-08-11 23:32:21+00:00)
Title: Small Shashlik reco speed improvement

@davidlange6 is this what you meant?

Functionally the same but the order of checks has been changed to improve speed. There is a minor side effect in that fewer debug printouts will occur when the previously-second "if" evaluates to false, so that the previously-first "if" (which would produce the printout) is skipped.
All plots are ttbar at 140 pileup in Shashlik; "before" plots include #4909.

**Total event times before and after**
![shashlikrecotimer-afterlangesuggestion-eventtotal](https://cloud.githubusercontent.com/assets/6480160/3884299/4a5ea692-21ad-11e4-8df1-31208a665e06.png)
This equates to a drop from 6.1+/-1.7 minutes to 5.9+/-1.8 minutes per event (mean+/-sqrt(variance)). Doesn't sound that impressive when stated like that, but they're the same events not random data.

**User time by module before**
![shashlikrecotimer-beforelangesuggestion](https://cloud.githubusercontent.com/assets/6480160/3884333/e458c354-21ad-11e4-8e8b-9dfb4e4c2b3b.png)

**User time by module after**
![shashlikrecotimer-afterlangesuggestion](https://cloud.githubusercontent.com/assets/6480160/3884337/ed3f8160-21ad-11e4-8d62-9c2fd3c57fcb.png)

Some modules appear to slightly increase in time (e.g. particleFlowTmp, particleFlowEGamma) but others significantly decrease (particleFlowBlock). I'm not sure how accurate the timing is so I suspect this is just noise.

Updated igprof file at /afs/cern.ch/user/g/grimes/public/SLHC16_patch1Preview/igreport_perf_ShashlikRecoAfterLangeSuggestion_15evt.res
@davidlange6, @lgray