[Halld-offline] Data Challenge Meeting Minutes, February 7, 2014

Mon Feb 10 13:35:37 EST 2014

People,

Find the minutes below and at:

https://halldweb1.jlab.org/wiki/index.php/GlueX_Data_Challenge_Meeting,_February_7,_2014#Minutes 
.

   -- Mark
_________________________________________________________________

GlueX Data Challenge Meeting, February 7, 2014
Minutes

    Present:
      * CMU: Curtis Meyer, Paul Mattione
      * FSU: Volker Crede, Aristeidis Tsaris
      * IU: Kei Moriya
      * JLab: Eugene Chudakov, Mark Ito (chair), Sandy Philpott, Simon
        Taylor, Beni Zihlmann
      * MIT: Justin Stevens
      * NWU: Sean Dobbs
      * UConn: Richard Jones

Agreed upon Parameters

    We reviewed the parameters listed in the [25]agenda above. There was no
    discussion and no changes were proposed.

Status of Preparations

JLab CC is ready, what do we need to tell them

    Sandy gave a report on preparations by JLab Scientific Computing.
      * The current farm is at about 1200 cores. The farm typically 1400
        cores. For the 25% level test we will need 1250 cores. The plan is
        to bring another 1000 cores over from LQCD to keep the farm
        generally usable.
      * One option is to end our data challenge at a power outage that is
        planned for some time during the next 6 to 8 weeks.
      * We estimate that we will need a full complement of nodes for about
        2 weeks.
      * Lattice nodes are available to us because Physics has been lending
        32 16-core nodes to the LQCD farm all of December and January.
      * It looks like the SRM capability is not a pressing problem for
        running this challenge at JLab, but does need to be addressed in
        the medium term. This issue will be discussed at the upcoming
        collaboration meeting.

Update on phi=0 geometry issues in CDC? Simon/Richard

    Simon sent a plot to Richard illustrating the problem. Beni has also
    done a study with lead CDC straws and geantinos in which he observed
    disappearing straws under certain circumstances. Richard has been able
    to reproduce the problem; it appears to involve the transition in the
    wrap-around from 359 going back to 0 degrees. He is studying the
    problem now.

Random number seeds procedure?

    No progress to report.

Electromagnetic Backgrounds update

    Kei showed [26]slides detailing studies he has done on the computing
    resources needed to generate EM background under various conditions. He
    tried two beam rates, corresponding to 10^7 and 10^8, and two time
    intervals, 400 ns and 800 ns. In addition to these four combinations he
    ran with no beam background at all. For the comparison between no
    background and 10^7 with an 800 ns gate, the output file size increases
    by about 10% but the execution time for the job (including bggen,
    hdgeant, mcsmear, and hd_root) nearly triples. The increase is mainly
    in hdgeant, as expected. He also did comparisons of the number of
    neutral showers, and deposited energy in the BCAL and FCAL separately.

    Paul was running at CMU with the recently defined versions (see below)
    and was seeing a third of his 10,000-event[?] jobs crash in
    reconstruction.

    Mark is also seeing crashes with these versions at JLab even though
    there is no EM background in his jobs. He showed a [27]wiki page where
    the success rate was only about 20% for 50,000 event runs with
    parameters unchanged from the first data challenge.

    We had been expecting that seg faults in the reconstruction were
    largely eliminated in recent weeks; this was a surprise to many of us.
    All aspects of the code and how it is configured need to be examined.

Check on event genealogy

    No progress to report.

Preparations of standard distribution/scripts

    Mark prepared tagged versions of HDDS and sim-recon yesterday and put
    up the [28]webpage for distribution of all relevant software versions
    and run-time configuration files. These were mentioned in the
    discussion above.

Report on data management practices

    Sean went over a quick survey he has done on various data management
    systems. Richard had asked him to do so at the last meeting. See
    [29]his slides for details. He described two systems in detail:
     1. a custom database with xrootd/SRM
     2. DIRAC toolkit

    In general he found documentation less than comprehensive. Also the
    ease of modifying systems for our purposes was not clear. We probably
    should postpone adoption of such a system until after this data
    challenge.

Open Stack Overview

    Justin described an effort at MIT to operate a cluster where users
    instantiate a virtual machine of their choice with their desired
    software stack when running on a node. See [30]his wiki page for
    details. The cluster to develop this system currently stands at 22
    blades with 8 cores each. The project is looking for users. Justin
    asked the group if this was something that we would like to pursue; he
    volunteered to implement the data challenge jobs as a demo and as an
    additional production site if things go well. We all thought it was a
    great idea.

Workflow Tools at JLab

    Mark reported that he talked to Chris Larrieu of SciComp and they are
    not ready to deploy a system in time for this data challenge. Curtis
    suggested that we invite Chris to future data challenge meetings.

Proposed Schedule

    We endorsed the schedule that Curtis proposed, reproduced below:
      * Launch of Data Challenge Thursday Feb.27, 2014 (est.).
      * Test jobs going successfully by Tuesday February 25.
      * Distribution ready by Monday February 24.

Action Items

     1. Look at the phi = 0 efficiency hole. -> Richard
     2. Understand random number seed saving and retrieval. -> Mark
     3. Test new genealogy scheme. -> Kei
     4. Settle on a realistic gate time for EM background. -> Kei
     5. Invite Chris Larrieu to future data challenge meetings. -> Mark
     6. Track the source of crashes in the reconstruction. -> All

    Retrieved from
"https://halldweb1.jlab.org/wiki/index.php/GlueX_Data_Challenge_Meeting,_February_7,_2014"

References

   25. 
https://halldweb1.jlab.org/wiki/index.php/GlueX_Data_Challenge_Meeting,_February_7,_2014#Agenda
   26. 
https://halldweb1.jlab.org/wiki/images/3/30/2014-02-07-DataChallenge2_EMrates.pdf
   27. https://halldweb1.jlab.org/wiki/index.php/Quick_Look_at_DC_2
   28. 
https://halldweb1.jlab.org/data_challenge/02/conditions/data_challenge_2.html
   29. 
https://halldweb1.jlab.org/wiki/images/6/6a/DataChallenge-20140207.pdf
   30. https://halldweb1.jlab.org/wiki/index.php/Openstack_at_MIT_Overview

-- 
Mark M. Ito, Jefferson Lab, marki at jlab.org, (757)269-5295