[Halld-offline] Software Meeting Minutes, March 16, 2021

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Software_Meeting,_March_16,_2021#Minutes> 
and below.

   -- Mark

      ______________________________________


    GlueX Software Meeting, March 16, 2021, Minutes

Present: Alexander Austregesilo, Thomas Britton, Mark Dalton, Sean 
Dobbs, Mark Ito (chair), Igal Jaegle, David Lawrence, Simon Taylor, 
Nilanga Wickramaarachchi, Beni Zihlmann

There is a recording of this meeting 
<https://bluejeans.com/s/y80vA_yXz9L/>. Log into the BlueJeans site 
<https://jlab.bluejeans.com> first to gain access (use your JLab 
credentials).


      Review of Minutes from the Last Software Meeting

We went over the minutes from March 2nd 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Software_Meeting,_March_2,_2021#Minutes>. 
We talked about the new scheme to assign photon energies to tagger hits.

  * Sean volunteered to look at patching the halld_recon code used in
    previous reconstruction launches to reflect the new scheme.
  * Sean suggested that we do some testing of the changes in Richard's
    pull requests before merging. We agreed to contact Drew Smith and
    ask if the changes solve his issue. Also Sean agreed to look at
    doing some tests. [Added in press: Alex did some testing, looking at
    the new REST format. He then went ahead and merged in those changes
    in halld_recon.]
  * Mark mentioned the idea of having the system stagger the start time
    of farm jobs at the SciComp meeting last week. This appeared to be a
    new concept to the gathered; it will have to be raised again if it
    is a feature we really want.
  * Mark has started meeting regularly with Dmitry Romanov on CCDB 2.0.


      Minutes from the Last HDGeant4 Meeting

We reviewed the minutes from the HDGeant4 Meeting on March 9 
<https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_March_9,_2021#Minutes> 
without significant comment.


      Report from the SciComp Meeting

Mark presented slides from Bryan Hess 
<https://halldweb.jlab.org/talks/2021/scicomp-ops-2021-03-edit2.pdf>, 
shown at the SciComp meeting on March 4th. Bryan had covered a lot of 
topics:

  * Network configuration changes
  * 100 Gb upgrade for our ESNet connection
  * Lustre issues
  * New Work Disk server
  * LT08 Tape Issue
  * Farm node expansion
  * OSG jobs running at JLab
  * ifarm slowness problem
  * Miscellaneous Notes
      o New SciComp computing status pages
      o Swif2 call for testers
      o GitHub contract changes
      o Upgrade path from CentOS 7

Please see his slides (linked above) for the details.


      The Pull-Request Tests System

Sean described the system we run for all new pull requests 
<https://halldweb.jlab.org/wiki/images/9/9c/Sdobbs_offline_20210316.pdf> 
for halld_recon and halld_sim. Both build and function tests are done. 
See his slides for the details.

Mark asked about whether we want to look at Travis CI 
<https://travis-ci.org/>, which is integrated with GitHub. The consensus 
was that using our local resources to do the test fits well with the 
structure of our software and if it ain't broke...


      Software Testing Discussion

The discussion never got of the ground due to network problems that put 
halldweb out of touch. We will try again next time.


      GPU-Equipped Farm Nodes

David told us that in the next round of purchases, in addition to 
spending $120 k on traditional CPUs, another $120 k will go to nodes 
with GPUs on-board. He asked if GlueX had plans to exploit this resource 
in the near future. He mentioned two areas of which he was already 
aware: machine learning based differentiation between photon showers and 
hadronic split-offs in the FCAL and amplitude analysis with AmpTools.

Alex reported that he has already been using AmpTools GPU capabilities 
on some of the farm nodes to do his spin density matrix analysis and 
that is working well for him. He suspects that he is the only one an 
JLab doing this. He mentioned that it is not obvious how to use GPUs for 
REST production.

David reported on a project he and others are working on to do charged 
particle tracking with a machine learning system. That is work in progress.

Simon thought that to reconfigure the current tracking algorithm to use 
GPUs was challenging and is not something that can be done in the near 
term.

Mark mentioned that he had heard of efforts at other labs to do tracking 
with GPUs. If machinery could be imported for use with our software, 
that might cut down on development time for us. He also remarked that 
track reconstruction is really the area where we would benefit the most 
from a reduction in processing time.

Sean wondered if kinematic fitting might be something that could be 
configured to run on a GPU. That sounded like an interesting direction 
to explore.


      Action Item Review

 1. Make sure that the automatic tests of HDGeant4 pull requests have
    been fully implemented. (Mark I., Sean)
 2. Finish conversion of halld_recon to use JANA2. (Nathan)
 3. Release CCDB 2.0 (Dmitry, Mark I.)


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