LOGO PROOF system for parallel MPD event processing Gertsenberger K. V. Joint Institute for Nuclear Research, Dubna

NICA scheme Gertsenberger K.V.2

Multipurpose Detector (MPD) The software MPDRoot is developed for the MPD event simulation, reconstruction of experimental or simulated data and following physical analysis of heavy ion collisions registered by the MultiPurpose Detector at the NICA collider. 3Gertsenberger K.V.

 high interaction rate (up to 6 KHz)  high particle multiplicity, about 1000 charged particles for the central collision at the NICA energy  one event reconstruction takes tens of seconds in MPDRoot now, 1M events – months  large data stream from the MPD: is estimated at 5 to 10 PB of raw data per year 1m simulated events ~ 50 TB  MPD event data can be processed concurrently  the ability to use multicore / multiprocessor machines, computing clusters and, subsequently, GRID system 4Gertsenberger K.V. Prerequisites of the parallel processing

Current NICA cluster in LHEP 5Gertsenberger K.V.

Data storage on the NICA cluster 6Gertsenberger K.V. Distributed file system GlusterFS  it aggregates existing file systems in a common distributed file system  automatic replication works as background process  background self- checking service restores corrupted files in case of hardware or software failure

Parallel MPD event processing PROOF server parallel data processing in ROOT macros on the parallel architectures concurrent event processing MPD-scheduler scheduling system for the task distribution to parallelize data processing on the cluster nodes 7Gertsenberger K.V.

Parallel data processing with PROOF  PROOF (Parallel ROOT Facility) is a part of the ROOT software, no additional installations  PROOF uses data independent parallelism based on the lack of correlation for MPD events  good scalability  Parallelization for three parallel architectures: 1.PROOF-Lite parallelizes the data processing on one multiprocessor/multicores machine 2.PROOF parallelizes processing on heterogeneous computing cluster 3.Parallel data processing in GRID system  Transparency: the same program code can execute both sequentially and concurrently 8Gertsenberger K.V.

Using PROOF in MPDRoot  The last parameter of the reconstruction: run_type (default, “local”). Speedup on the user multicore machine: $ root reco.C(“evetest.root”, “mpddst.root”, 0, 1000, “proof”) parallel processing of 1000 events with thread count being equal logical processor count $ root reco.C(“evetest.root”, “mpddst.root”, 0, 500, “proof:workers=3”) parallel processing of 500 events with three concurrent threads Speedup on the NICA cluster: $ root reco.C(“evetest.root”, “mpddst.root”, 0, 1000, parallel processing of 1000 events on all cluster’s cores of the PoD farm $ root reco.C(“evetest.root”, …, 0, 500, parallel processing of 500 events on the PoD cluster with 15 workers  XRootD files support 9Gertsenberger K.V.

The speedup of the reconstruction on 4-cores machine 10Gertsenberger K.V.

PROOF on the NICA cluster 11Gertsenberger K.V. proof proof = master server proof = slave node *.root GlusterFS Proof On Demand Cluster (10) (14) $ root reco.C(“evetest.root”,”mpddst.root”, 0, 3, event count evetest.root event №1 event №2 mpddst.root event №0

The speedup of the reconstruction on the NICA cluster 12Gertsenberger K.V.

The description of PROOF system on mpd.jinr.ru 13Gertsenberger K.V.

Conclusions  The distributed NICA cluster was deployed on LHEP farm for the NICA/MPD experiment (Fairsoft, ROOT/PROOF, MPDRoot, Gluster). 128 cores  The data storage was organized with the GlusterFS distributed file system: /nica/mpd[1-8]. 10 TB  PROOF On Demand cluster containing nc10 (with POD server), nc11 and nc13 machines with 34 processor cores was implemented to parallelize event data processing for the MPD experiment. PROOF support was added to the reconstruction macro.  The web site mpd.jinr.ru in section Computing – NICA cluster – PROOF parallelize presents the manual for the PROOF system. 14Gertsenberger K.V.