TeraGrid Gateway User Concept – Supporting Users V. E. Lynch, M. L. Chen, J. W. Cobb, J. A. Kohl, S. D. Miller, S. S. Vazhkudai Oak Ridge National Laboratory In collaboration with many teams: NSTG, SNS Scientific Computing, McStas group, Open Science Grid, Tech-X Corp, and the TeraGrid Partners teams.

What is a Science Gateway?  A Science Gateway  Enables scientific communities of users with a common scientific goal  Uses high performance computing  Has a common interface  Leverages community investment  Three common forms:  Web-based Portals  Application programs running on users' machines but accessing services in TeraGrid  Coordinated access points enabling users to move seamlessly between TeraGrid and other grids.

How can a Gateway help?  Make science more productive  Researchers use same tools  Complex workflows  Common data formats  Data sharing  Bring TeraGrid capabilities to the broad science community  Lots of disk space  Lots of compute resources  Powerful analysis capabilities  A nice interface to information

What is the TeraGrid? 4 SDSC TACC UC/ANL NCSA ORNL PU IU PSC NCAR Caltech USC/ISI UNC/RENCI UW Resource Provider (RP) Software Integration Partner LONI NICS Grid Infrastructure Group (UChicago) (GIG) GIG 20 computers at 11 facilities 10Gbps network Over a petaflop of computing power 136,470 CPU-cores 60 petabytes long-term storage Growing

Neutron Science TeraGrid Gateway  Focus is neutron science  Connects facilities with cyberinfrastructure  Bridges cyberinfrastructure  Combines TeraGrid computational resources with neutron datasets  Data movement across TeraGrid  Outreach to neutron science 5

Community Certificate and Account  Gateways with community accounts scale to thousands of facility users  Have Jimmy Neutron community accounts on 14 TeraGrid computers  Use Jimmy Neutron Community Certificate from SNS community account  Record end-user identification for auditing and return of results 6 Community Account

7 TeraGrid Before Gateways  Large facilities:  Recorded histogram data from experiments  Users:  Took their data home on floppy disk in pocket  Saved permanent copy on hard disk  Did not have event data to change histogram  Translated data into format needed for analysis  Wrote their own code to read and analyze data  Installed discipline focused software on their PC for analysis  Installed plotting programs/libraries to plot analysis output

8 TeraGrid After Gateways  Large facilities:  Record data from multiple facilities  SNS, HFIR, LENS, IPNS, LUJAN, …  Save permanent copy of raw data  Bin event data into histogram  Translate data into standard NeXus format  Have analysis and simulation programs available from portal  Use remote TeraGrid cyberinfrastructure for computations  Have visualization capability in portal  Users:  Use portal from web for all data, analysis, and visualization

9 TeraGrid Gateway Savings  Users do not duplicate efforts  Facilities do not duplicate efforts  Data is not lost  Data is easily shared  Natural way to integrate community contributed instrument specific software for hosting and wide availability to many facility users  Analysis is done quickly on high performance computers

10 TeraGrid Portal submit to TeraGrid

11 TeraGrid Simulation Service  Simulation of neutron instrument is available in portal with McStas  Simulations agree with experimental results  Linear scaling to 1024 cores  Output is NeXus  Use cases:  Instrument design and construction  Experiment planning and analysis

Fitting Service Fits theoretical models to the NeXus data files from the experiments Adaptive nonlinear least squares algorithm implemented in parallel Linear speedup to 32 cores Service to run on TeraGrid 12 TeraGrid

Reduction Service Reduction software is available tor backscattering and reflectometry through portal Calculations will be sent to local cluster and TeraGrid Attempted to parallelize this calculation by distributing regions of the time-of-flight to each processor. Each processor read only its region of the NeXus input data file and write a new file containing only that region. Each processor performs the data reduction on its file. The results are merged at the end of the calculation 13 TeraGrid Backscattering Data Reduction Reflectometry Data Reduction

Job Information Service 14 TeraGrid Portal Job Information Service tells where jobs is running, when it started and status Daily tests of submitting five simultaneous remote portal jobs Percentage success is > 82%

Tests of Remote Job Submission 15 TeraGrid Difficult to diagnose the problem from the Globus output. - Check the status of the computer - Look at the output files Some problems diagnosed: - Updated software on a computer that required relinked executables - Globus software setting the wrong time limit - Batch prologue script that killed jobs on same core - Long queue waits - Firewall installed

Conclusions  Gateways help facilities scale to a large number of users  Gateways give facilities access to high performance computing such as the TeraGrid  Gateways enable a scientific community to use community software through a common interface  Researchers are more productive if they use the same tools, use a common data format, and share data easily 16 TeraGrid