[Halld-offline] Minutes, GlueX Offline Software Meeting, March 9, 2011

[Mark M. Ito]

Find the minutes at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_March_9%2C_2011#Minutes 
and below as text.

    ==

GlueX Offline Meeting, March 9, 2011

Minutes

    Present:
      * CMU: Will Levine
      * IU: Mihajlo Kornicer, Ryan Mitchell, Kei Moriya
      * JLab: Hovanes Egiyan, Mark Ito (chair), Richard Jones, David
        Lawrence, Yi Qiang, Igor Senderovich, Sascha Somov, Simon Taylor,
        Elliott Wolin, Beni Zihlmann


Review of minutes from the last meeting

    We went over the [33]minutes of the February 23rd meeting.
      * We talked a bit about compiler warnings generated in our builds, in
        particular those that come from the FORTRAN code. Richard thought
        that eliminating all such warnings would involve playing with
        legacy code and may be more trouble that it is worth.
      * Mark has been in email contact with Dmitry. Dmitry plans to
        continue work on the calibration database soon.


The Meaning of DEBUG

    David reviewed his [35]recent message describing a richer set of
    options for compiler flags to support debugging symbols, profiling
    information, and optimization in our code. Mark thought that we should
    retain the "standard" default behavior of the DEBUG option to the make
    system (a.k.a. BMS): to generate debugging symbols and to turn off
    optimization. At present, at variance with past practice, these are
    controlled by independent options (DEBUG and OPTIMIZE). Elliott
    endorsed Mark's idea as in keeping with his "principle of least
    astonishment" [reference needed]. We agreed to go back to the
    traditional practice. Optimization will still be settable arbitrarily
    with explicit inclusion of the OPTIMIZE option.

SIMD enabling status

    Simon reminded us of recent history. At the end of last year, single
    instruction multiple data (SIMD) instructions were introduced into the
    Kalman filter to speed up the code. It was also made the default. A
    SIMD-free option was added to the BMS in January because problems
    started to appears for various other chips for which the code had not
    been tested. Recently Simon has changed the options to default to the
    non-SIMD version everywhere.

    We had a discussion on how to treat this issue in the long run. Various
    combinations of streaming SIMD extensions (SSE) are supported depending
    on the particular CPU architecture. Code compiled for one processor may
    not run on another. Even when used in a manner consistent with a
    particular CPU, results can vary (round-off effects) for the same code
    run on the same processor depending on whether SSE is enabled or not.

    Richard thought that we should leave things as they are for now, with
    the default being non-SIMD, until a consistent approach to exploiting
    this CPU feature for GlueX is formulated.

Offline Computing Requirements and the Grid

    David has been organizing a set of meetings to discuss what role the
    grid should be playing in our offline computing plans, if any. Two have
    been held so far, another is scheduled for tomorrow. We seem to be
    coalescing around a desire for a robust storage resource manager (SRM)
    capability at JLab to feed off-site grid-based clusters.

Action Item Review

    We went over recently-resolved and still-outstanding items. See the
    links in the [39]agenda above.

New Action Item

      * Re-organize the Software Wiki page. -> Mark


Recent Repository Activity

    We looked at the comments accompanying changes in our subversion
    repository over roughly the last two weeks. See the link in the
    [42]agenda above.

    Retrieved from
    
"http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_March_9%2C_2011"

References

   33. 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_February_23%2C_2011#Minutes
   35. 
https://mailman.jlab.org/pipermail/halld-offline/2011-February/000524.html
   39. 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_March_9%2C_2011#Agenda
   42. 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Offline_Meeting%2C_March_9%2C_2011#Agenda