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Planck Simulations. Status of the Application C. Vuerli, G. Taffoni, A. Barisani, A. Zacchei, F. Pasian INAF – Information Systems Unit and OA Trieste Geneve, 1 March 2006. Outline. Description of the Application and Scientific goals The Grid added value

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planck simulations

Planck Simulations

Status of the Application

C. Vuerli, G. Taffoni, A. Barisani, A. Zacchei, F. Pasian

INAF – Information Systems Unit and OA Trieste

Geneve, 1 March 2006

  • Description of the Application and Scientific goals
  • The Grid added value
  • Experiences and results with using the EGEE infrastructure
  • Future perspectives and issues for use of Grid Technology
  • Summing up status

Wednesday 1 March 2006

description the planck mission
DescriptionThe Planck Mission
  • Measure cosmic microwave background (CMB)
    • succeeds COBE, Boomerang & WMAP missions
    • aims at even higher resolution
  • Timeline
    • launch August 2007
    • start of observations 2008
    • duration >1 year
  • Characteristics
    • continuous data stream (TOD)
    • large datasets(a TOD of ~7 TB for the whole LFI mission)
    • changing calibration (parameters configuration)
    • high-performance computing for data analysis

Wednesday 1 March 2006

description cobe planck
DescriptionCOBE & Planck

Wednesday 1 March 2006

description brief introduction
DescriptionBrief introduction
  • Goal: make possible N simulations of the whole Planck/LFI mission (~14 months), each time with different cosmological and instrumental parameters
  • Full sky maps production for frequencies 30-857 GHz by means of two complete sky surveys
  • Sensitivity of a few μK per pixel 0,3° in amplitude
  • 22 channels for LFI, 48 for HFI
  • Data volume produced at the end of the mission: ~2TB for LFI and ~15TB for HFI
  • Computing requirements: ~100Tflops for raw data reduction, foregrounds extraction and CMB maps creation

Wednesday 1 March 2006

description the level s
DescriptionThe Level-S
  • Purpose of the Level-S:
    • ground checks (pre-launch phases);
    • DPCs Pipelines tuning;
    • control check & corrections (operational phase).
  • Pipeline chained but not parallel(43 executables and a few libraries)
  • Languages used are C/C++/Fortran/F90;
  • Shell/Perl for scripts;
  • Typical application that benefits by distributed computing techniques
  • Porting of Monte Carlo simulation code by Sam Leach

Planck simulation is a set of 70 instances of the Pipeline (22 for LFI and 48 for HFI)

Wednesday 1 March 2006

description the level s1
DescriptionThe Level-S


CMB Power Spectrum(cmbfast)

CMB maps

CMB Map(synfast)


Foregrounds andBeam Patterns


Scanning Strategy

Instrumental Noise

Wednesday 1 March 2006

description our application in summary
DescriptionOur application in summary
  • Is it parallel? NO it runs concurrently.
  • Do we need MPI/parallel? Yes. In later phase for data analysis (16/32 CPUs in the site).
  • How long does it run? From 6h (short) up to 36h (long)
  • Do we produce data? YES, we have an intensive data production. Can be more than 1 PB.
  • Access to/exchange of data coming from other experiments (IVOA, MAGIC)

Wednesday 1 March 2006

grid added values cpus and data
Grid added valuesCPUs and Data
  • CPU power:
    • E-computing lab;
    • Production burst;
    • Efficient CPU usage/sharing.
  • Data storing/sharing:
    • Distributed data for distributed users;
    • Replica and security;
    • Common interface to software and data.

Planck simulations are highly computing demanding and produce a huge amount of data. Such resources cannot be usually afforded by a single research institute, both in terms of computing power and data storage space.

Wednesday 1 March 2006

grid added values qualitative view
Grid added valuesQualitative view
  • Native collaboration tool;
  • Common Interface to the users;
  • Flexible environment;
  • New approach to data and S/W sharing;
  • Collaborative work for simulations and reduction:
    • less time, less space, less frustration….
  • VObs view:
    • Sharing data over a shared environment;
  • Native authentication/authorization mechanism;
  • A federation of users within a VO fosters the scientific collaboration;
  • Collaborative work between different applications.

Wednesday 1 March 2006

experiences and results first tests
Experiences and ResultsFirst Tests
  • First tests performed on a workstation aimed at identifying the computational and storage needs of the simulation SW in detail

Computational time on a dual CPU 2.4 GHz workstation with 2 GB of RAM for the whole simulation of the LFI mission

[4 radiometers at 30 GHz, 6 at 44 GHz and 12 a 70 GHz]

Wednesday 1 March 2006

experiences and results grid environment
Experiences and ResultsGrid Environment
  • To allow users to run Planck simulation SW we need to create some specific services on Grid general environment;
  • They must be used to run both one or more SDPs (Single Detector Pipeline) or the whole MSJ (Mission Simulation Job);
  • They are modular and easy to integrate with new pipeline stages when some upgrade is needed (this is necessary if we want to allow users to develop new codes).

Wednesday 1 March 2006

experiences and results grid environment1
Experiences and ResultsGrid Environment
  • Step 1: Deployment of the simulations code on the Grid as RPMs. In this first test however we used the Replica Manager to copy and register the SW.
  • Step 2: Creation of an application specific environment on top of the UI: a set of Perl scripts are available allowing a user to configure a pipeline and submit it to the Grid.
  • Step 3: Implementation of a metadata description to identify the cosmological and instrumental parameters and to associate them to the GUID of a complex output file (TODs, maps, noise contributions etc.) Important for post processing analysis.

Wednesday 1 March 2006

experiences and results simulations description
Experiences and ResultsSimulations description
  • A number of test simulations of the MSJ run with the same parameters used on the dual-CPU WS;
  • Initially selected only the Grid sites equipped with Xeon WNs at CPU speed of ~2400 and sites with at least 1 free CPU;
  • Run sets of MSJ with different degree of parallelization;
  • Tests repeated 30 times under different load conditions of the Grid to verify the stability of both the submission tools and of the Grid environment.
  • We noticed that RB usually assigns each SDP to a different site, so the MSJ runs on a truly distributed environment. However, a few times the jobs were assigned to the same site but to different WNs. As expected, no significant benefit or decay in performance was noticed in those cases. Also different Grid load did not change significantly the results.

Wednesday 1 March 2006

experiences and results simulations description1
Experiences and ResultsSimulations description
  • Set of tests involving the whole computing power and data storage available to our VO (~5000 CPUs of different kind). Submission of 100 concurrent MSJs from different UIs with the only requirement of finding enough free disk space to save the output.
  • Tests span two years starting from summer 2004 and using different versions of the MW (2.2, 2.4 and 2.6) and within different VOs
  • The whole test lasts for ~3 days and was repeated different times under different load conditions of the Grid with no significant change in the results
  • Long simulations could require to modify CFTSIO to allow I/O directly on Grid through GridFTP

Wednesday 1 March 2006

experiences and results post processing example
Experiences and ResultsPost-processing example
  • To verify the possibility of using the stored TODs for some kind of post-processing we applied the destriping algorithm on the TODs produced during the short runs.
    • Metadata are used to locate the files and to identify their GUIDs.
    • The configuration/submission Planck tools are modified to create a JDL with the input-file option that points to the TOD GUID.
    • The input-file option is used by the RB to force the job to run in the Grid site where the input data are stored. This optimizes the data transfer which is in this way restricted to the site LAN.
    • The Grid "configurator" is modified to download any input data file specified in the input-file option before running the pipeline.

Wednesday 1 March 2006

experiences and results post processing example1
Experiences and ResultsPost-processing example
  • The “destriping” procedure runs for ~20 minutes for 30 GHz channel up to ~40 minutes for the 70 GHz channel on a dual AMD workstation.
  • On Grid the run time for a simulations set of 22 radiometer is ~55 minutes with a gain of a factor of 10 in performances compared with times required on the workstation.

Wednesday 1 March 2006

experiences and results post processing example2
Experiences and ResultsPost-processing example

User Node







Node k

Node 1




maps, TOD

maps, TOD

observed sky after de-striping

Dual CPU WS 2,4 GHz with 2 GB di RAM vs. Grid

map of de-striping residuals

Wednesday 1 March 2006

future perspectives and issues proc and g dse
ProC is a scientific workflow engine developed in the framework of IDIS (Integrated Data and Information System) collaboration

It executes “pipelines” of modules

Workflows, directed “acyclic” graphs

It allows the assembly of Pipelines using building block modules

Modules may be heterogeneous (FORTRAN, C, C++, Java, Python, GDL/IDL, ...); also sub-pipelines

It is a data-driven, forward-chaining system

It has components for ...

graphical editing of workflow layouts

checking for consistency & completeness


The G-DSE makes of databases a new embedded resource of the Grid. It enables a new Grid QE to access databases and use them for data analysis (see presentation by G. Taffoni on Thu March 2nd, 2006, at 2.00 PM “Data Access on the Grid” session)

Future Perspectives and IssuesProC and G-DSE

Wednesday 1 March 2006

future perspectives and issues planck vo evolution
Future Perspectives and IssuesPlanck VO Evolution
  • Users who joined the VO 15-30 members;
  • UI in each site;
  • Quantum-Grid in each site;
  • VO Planck may currently rely on ~5000 available CPUs

Wednesday 1 March 2006

future perspectives and issues open issues
Technical and administrative management of the VO  OK

Basic gridification of the Application  OK

Main issues met in 2005

Slow startup process of Planck VO

Slow start up of interactions between Planck VO site managers and national ROCs

Some technical initial problems (e.g. VOMS)

The management of the VO has proved to be more complex with respect our expectations

Heterogeneous VO

Some problem on WN environment

Metadata = DSE (work in progress)

Grid-FS complicated and not user-friendly


Future Perspectives and Issues Open issues

Wednesday 1 March 2006

future perspectives and issues effects corrective actions
Future Perspectives and Issues Effects/corrective actions
  • …therefore:
    • Still missing shared resources within the VO
    • The gridification of Planck pipelines has still to be completed
    • Until now extensive tests involving all nodes of the VO were not possible
  • Corrective action
    • On-site (at VO sites) meetings and training events (involving Planck and INAF VOs) addressed to site managers and users and scheduled for the next months for a:
      • Fast startup of VO nodes with new shared resources available;
      • Gridification of new pipelines;
      • Extensive tests within the VO.
  • Future strictly dependent from a number of factors: gLite (!?!), support (?), EGEE-2 (?)

Wednesday 1 March 2006

summing up status
VO Setup:


Technical Management;

VO manager;

Site managers;




Planck users cert;

Planck sites setup;

EGEE site support.

Application Setup:

Basic Gridification;

First tests;

INFN production Grid;


Extended gridification;

Data&metadata (GDSE!!!);

ProC & DMC gridification;




Summing up status

Wednesday 1 March 2006

end of presentation
End of Presentation

End of Presentation

Thank you for your attention

Wednesday 1 March 2006