Strategy document for LHCC – Run 4 Ian Bird MB 14 Nov 2017 MB, 14 Nov 2017

Process Community White Paper Ideas and aspirations from across broad section of HEP; wider than just HL-LHC End 2017 – WLCG Strategy Document for LHCC WLCG-specific view of CWP Key topics for HL-LHC Prioritised R&D programme for the next several years Mid-2020 – TDR for HL-LHC Computing Probably with an “external” review Will not be “the computing model” but developed aspects of the strategy, and continued R&D programme Have to ensure it is understood that there is no ”final model” Has to indicate cost of computing (essentially flat budgets – but with more words) MB, 14 Nov 2017

LHCC strategy vs CWP? CWP is a broad bottom-up review by the HEP community Albeit with a focus on HL-LHC No real prioritisation LHCC require a strategy for R&D that leads towards the TDR in 2020 By construction the CWP is a large part of that process The strategy document is a WLCG-view, that: Tries to prioritise where investment (R&D, changes) is likely to have a significant impact on overall cost, and optimises physics output Sets out the R&D programme for the coming years Leads towards a cost estimate for HL-LHC computing Relies on the details in the CWP MB, 14 Nov 2017

Document outline Introduction Themes that address cost and performance Update of the resource requirements estimates Themes that address cost and performance Next slide R&D programme & timescale MB, 14 Nov 2017

Key strategies to manage cost Software performance and efficiency Fabric performance & efficiency, including data access This cuts across all applications Minimise data volumes HLT processing, selection, nano-AODs Reduce replication Remote (bulk) processing without need to ship data Cloud analysis Reduce processing costs Fast simulation will be a huge benefit Improved/new algorithms (ML/DL is seen as important technology) Minimise operations costs Consolidation or federation at National level Common solutions for infrastructure & software stacks Move common services (data, workflow) into infrastructure layers Sustainability Common solutions and joint efforts Common infrastructure – across HEP and with other related sciences Authentication/authorization infrastructure – which direction? Data preservation and reproducibility Non-exhaustive list MB, 14 Nov 2017

Summary Outline proposed Timescale agreed with LHCC is first LHCC meeting in 2018 (Feb) As CWP was later than anticipated Will be reviewed by MB and OB MB, 14 Nov 2017