[Halld-offline] Offline Meeting Minutes, July 8, 2015

Mark Ito marki at jlab.org
Fri Jul 10 12:32:21 EDT 2015


Please find the minutes below and at


   -- Mark

Minutes, GlueX Offline Meeting, July 8, 2015


  * *FIU:* Mahmoud Kamel
  * *JLab*: Alex Barnes, Mark Dalton, Mark Ito (chair), David Lawrence,
    Paul Mattione, Curtis Meyer, Eric Pooser, Matt Shepherd, Justin
    Stevens, Simon Taylor, Beni Zihlmann
  * *NU*: Sean Dobbs


 1. *Sim-Recon 1.3.0.* Mark reminded us of the latest release
    It is compatible with JANA 0.7.3 and uses a new BCAL smearing scheme
    from Tegan Beattie.
      * CLHEP is no longer needed by AmpTools and comes packaged with
        Geant4 in recent versions. It will be dropped from the packages
        built by default by the GlueX Version Management System (GVMS).
 2. *Legacy build directories.* Some old directories in the
    /group/halld/Software/builds directory at JLab are about to
    disappear. Lately they have been a source of confusion. See Mark's
    email message
    for details.

Review of minutes from June 24

We went over the minutes from last time 

  * The switch to the new volatile disk hardware went without a hitch.
  * The Data Center power outage went well as well.
  * Mark I. is still promising to send out instructions on how to switch
    from use of one of the various builds of GlueX software to another.
  * Mark and Beni have succeeded in building the complete suite of GlueX
    software on Beni's Ubuntu machine. The next step is to set up a
    nightly build.
  * Beni has succeeded in creating a working build of GlueX software
    against a version of ROOT 6. We will need to discuss an upgrade in
    the future.

Offline Monitoring Train Schedule and Status

Paul reported that the plan is to launch the next offline monitoring 
train this Friday. There was no train last week.

Sean gave us an update on offline monitoring post-processing. His slide 
reads as follows:
Offline Monitoring Backend

  * The system is ready for the next run
  * Memory usage under control - ~1 GB per process
  * pylint is your friend
  * Parallelized hadd - phadd
      o Uses python thread pooling
      o Current settings: 6 threads, 10 files in a batch. On ifarm,
        limited by bandwidth to work disk
      o Run 2439: ~40 min (hadd) -> ~14 min (phadd)
      o N.B. hadd -n processes batches serially, uses less memory but
  * Ready to monitor simulations
  * Processing of online histograms works now, too

He also mentioned:

  * The next step is a webpage to show results.
  * We need a similar set of procedures for simulation.
  * We should think about running something for the online as well.

Spring 2015 Commissioning Simulations

Sean updated the status of the simulation 

We have to finalize the monitoring plugins we want to run and then we 
will be ready to go. Test jobs have run successfully.

Justin explained why some jobs are timing out. We moved the boundary 
between using Pythia and Eugene's PDG compilation of decay modes down to 
2.5 GeV from the nominal 3.0 GeV, an energy below the coherent peak. 
Otherwise we would get no omega's or phi's at the peak energy. This 
causes bggen to go into an infinite loop sometimes. There is still an 
acceptable fraction of jobs which complete normally so we are just 
accepting that yield.

Proposal on Git for GlueX

Mark ran down a proposal for the change from Subversion to Git. See his 
slides <https://halldweb.jlab.org/talks/2015/git_for_gluex_3.pdf> for 
the details. One of the slides addressed the procedure for switch-over:

 1. Comment: Only HDDS and sim-recon will be converted.
 2. Comment: Having two authoritative repositories is a contradiction in
 3. Schedule switch-over for COB, Wed., July 15.
 4. Between now and then, people should check in changes to the
    Subversion repository.
 5. Continue to get experience using practice repositories.
 6. Do final conversion from Subversion to Git overnight, Wed. to Thu.
    Practice repositories will be deleted.
 7. Open for business for Git after all-clear announcement Thursday morning.

We had a vote and there were no votes opposing the change.

JANA 0.7.3

David described changes in the new release of JANA. See his slides 
<https://halldweb.jlab.org/wiki/images/4/41/20150708_JANA0.7.3.pdf> for 
details. He highlighted a few of the new features:

  * *janaview plugin*. A system for click and point browsing of event
  * *support stdin types in janaroot*. Automatic creation of ROOT trees
    for selected factory-made objects.
  * *Fixed longstanding bug in jgeomread where attributes specified in
    the middle of the xpath were not displayed*.
  * *JObject:Get() does recursive searches for associated objects*.
  * *Event Barriers*. Ability to synch event processing threads on
    special events such as EPICS events.
  * *Added --listconfig switch*. Dump the JANA configuration to the screen

Geant4 Update

Richard gave a report.

  * There is a project on GitHub now: https://github.com/rjones30/HDGeant4 .
  * He described the workflow
    <http://nvie.com/posts/a-successful-git-branching-model> he is
    supporting for development work.
  * Building the code using the magnetic field mechanism used in DANA
    has been solved.
  * David has suggested starting with Geant4 10 since that incorporates
    multi-threaded particle tracking. Because of custom fixes to the
    Geant4 code that Richard has developed, the same code will not run
    under both version 9 and 10.
  * The single particle gun works now among other features.

multi-threaded mcsmearing

David described a study he did that compared performance of mcsmear with 
different settings of output compression and different numbers of 
threads. See his log book entry 
<https://logbooks.jlab.org/entry/3344045>. Adding threads has very 
little effect on execution speed, but requesting compression adds over a 
factor of two to the execution speed. In the usual context where we are 
interested in reconstructing the data as soon as it is smeared, the 
intermediate smeared file will not be shipped around and compression 
helps very little. Richard pointed out that the connection between 
mcsmear and DANA could be through a named pipe to avoid the disk 
write/read overhead altogether.

Mixing Simulated Events

We decided to defer Sean's talk until next time.

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