Report on CHEP ‘06 David Lawrence

Conference had many participants, but was clearly dominated by LHC LHC has 4 major experiments: ALICE, ATLAS, CMS, and LHCb Collaboration sizes: ~500, ~1000, ~1000, ~2000

LHC Event and Data Rates Event Size (bytes) L1 trigger rate Data rate Atlas1.6 x kHz120 GB/s CMS1.0 x kHz100 GB/s Alice1.0 x kHz20 GB/s LHCb3.5 x MHz3.5 GB/s

PHENIX DAQ system used LZO compression to compress raw data after the event builder –Reduced bandwidth requirement –Reduced disk space requirement –Extended time data allowed to linger in buffer boxes

PHENIX Buffer boxes: The longer you can buffer data the better you can take advantage of breaks in data flow. 6 reasonably cheap Linux-based buffer boxes (~20k each) allow 40 hours of data taking without tape access. L3 trigger can be run on disk data so it only needs to keep up with the average event rate, not the peak rate.

PHENIX Analysis Trains: Improve overall use of resources by limiting random access of data files. About every 3 weeks a new train is started. Jobs register with train ahead of time. Tapes are read in tape-order and all jobs run on the data at once.

PHENIX 270 TB of data was shipped to computing center in Japan for processing This was done by non-experts manning shifts

ROOT ROOT is now 11 years old and represents ~500 man-years of effort

ROOT The 2016 laptop: 32 processors, 16GB RAM, 16TB of disk Multi-core processors are at the doorstep and better multi-threading support is needed. PROOF I/O (read-ahead) Fitting/Minimization …

ROOT STL and templates take significantly longer to compile. Shared libraries become less efficient as the number of packages implemented in them grows The new ROOT will be BOOT

GDML Witold Pokotski of the GDML development team Repeated structures are now supported AGDD guys seem to think they have a better product and are still a bit bitter I suggested GDML implement the ability to apply tweaks in a separate file from the default geometry (they’ll think about it)

What do you know, people do develop and run physics analysis software on MS Windows!

Object Persistence Some LHC experiments use POOL which uses Reflex outside of ROOT and then defines TTrees using the Reflex information.

Object Persistence ROOT I/O has many new features making it more viable candidate for general use ROOT I/O is based on the Reflex project which uses gccxml

IEEE Transactions in Nuclear Physics Refereed Journal pushing for publications from CHEP type work (software) “Hardware guys are very good at publishing. Software guys need to do better then they are.”

Conclusions An abstract really, really should have been submitted for DANA We need to publish (e.g. IEEE TNS) ROOT is very strongly supported and will continue to be developed over at least the next 6 years CHEP 2007 will be in Victoria, BC. I will be there