Upgrade Software University and INFN Catania Upgrade Software Alessia Tricomi University and INFN Catania CMS Trigger Workshop CERN, 23 July 2009

Disclaimer More than a real presentation this talk is meant to “trigger” discussion about future software developments/strategies CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 2

3 Goals for SLHC Software (Re)use as much of the code in CMSSW as possible Cause zero disturbance (or confusion) for standard CMS code Low maintenance for upgrade code (releases) Enable upgrade simulation studies by non-code experts Common code base for meaningful comparisons of studies from different people/working groups

SLHC software: where we are? During May workshop we had a first session on SLHC workshop Overall a positive experience First time we met “officially” with offline experts Many ideas came for the first strategies In the last two months much more experience gained The code is becoming more and more complex The code is becoming more and more stable We went through a dedicated production phase (see Dave’s talk) Very good experience But many points were raised CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 4

Strategies for SLHC Software: status as May workshop Two possible strategies Dedicated release Heavy in term of maintenance – need dedicated manpower resources CVS Branches We decided to adopt this strategy Manage upgrade code through CVS branches Possible due to limited number of packages/files modified Start CVS branch (each time!) at a stable release Upgrade-only files in separate SLHCUpgradeSimulations CVS package SLHCUpgradeSimulations/Geometry SLHCUpgradeSimulations/L1Trigger SLHCUpgradeSImulations/Utilities SLHCUpgradeSimulations/Validation CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 5

6 SLHC Upgrade Software: status up today! Overall a positive experience so far with current method of working PRO: Can use all new CMSSW code and features easily Much less effort than keeping a separate copy of CMSSW for upgrades Direct connection to standard code for comparisons –Easier to get help from experts (Thanks to all experts for all help so far!) Surprising how much of the software can be used (thanks to Offline!) CON: needs recompile (change to e.g. data format need care) CON: Need to create new branch for each stable release Can have many changes between stable releases to adapt upgrade sw to Continue to work with CVS branches at least until we have a more stable code

SLHC sw strategy: PRO/CON This strategy was adopted for our first production since there was urgency to produce samples using existing code need to share samples No manpower to go towards a dedicated release Code still in a debugging phase Dave will report on such experience… However some limits of current strategies (already well known) are becoming more and more important No official release means no official production Only partial use of GRID facilities CVS branches/tags growing more and more CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 7

How to move on… Longer timescale (but not too longer!) – we need to produce the first TDR for PhaseI in April-May 2010 Need to quantify resource requirements CPU Memory Storage CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 8

CPU/Time issue Common to all sub-detectors - just an examples… CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 9

Memory issue Common to all sub-detectors - just an examples… CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 10

Storage etc. Very large files especially with high PU This is true both with full and fast simulation We need to set the minimum info needed for performance studies that we would like to save on file Very large production of minimum bias needed I/O problems? How to access these data from remote? CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 11

SLHC sw: how to move on… For the next months We need dedicated Monte Carlo productions We need to exploit a whole use of GRID resources We need to build up an efficient production/validation chain for large MC production We need to share our data Last but not least we need to solve problems with memory/cpu Not easy to find farm with needed resources Also storage could become an issue We need to revisit our sw code development to solve memory issue –We need experts help CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 12

Action items/Discussion points We need to target a set of “good” GRID sites We intend to set up an ‘SLHC group’ (in CMS computing terms) Proposed contacts: D. Newbold / A. Tricomi This already agree with Offline/Computing managers Should we move to 3_1_x? Advantages: keep in touch with experts Ask for a dedicated release and so also for official production Experts claim that many issue with high PU are solved Disadvantages: Migration is a very expensive in time Still not very stable CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 13

Action items/Discussion points My personal opinion is that we should move to 3_1_X and try to easy all the machinery However, since it is very time consuming and we need also to produce first results, I suggest we wait September before starting to move To plan future production/work it could be useful to know for each sub-detector How many events we need Which is the size of one full event How long it last to produce one event How many memory is needed Do you need fast or full sim? Do you need standalone or global detector info? All together we should decide Which sample we are interested in for global detector simulation How many events Timescale CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania) 14

It is really time to start to organize and better integrate our software/efforts! 15 CMS Trigger Upgrade Workshop, 23 July 2009 A. Tricomi (Catania)