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Design of. Departmental Metacomputing ML. Frédéric Gava. Goal. Computing Unit. Computing Unit. Storage. User. Bulk Synchronous Parallelism + Functional Programming = BSML. A d vantages of the BSP mod e l: P or tability Scalability, deadlock free
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Design of Departmental Metacomputing ML Frédéric Gava ICCS 2004 Gava
Goal Computing Unit Computing Unit Storage User ICCS 2004 Gava
Bulk Synchronous Parallelism + Functional Programming = BSML • Advantages of the BSP model: • Portability • Scalability, deadlock free • Simple cost model Performance prediction • Advantages of functional programming: • High level features (higher order functions, pattern-matching, concrete types, etc…) • Savety of the environment • Programs Proofs ICCS 2004 Gava
The BSP model 0 1 2 3 p-1 Proc. T(s) = (max0i<p wi) + hg + L
The BSML language • Confluent language : deterministic algorithms • Library for the « Objective Caml » language (called BSMLlib) • Operations to access to the BSP parameters • 4 Operations on a parallel data structure called parallel vector • mkpar : create a parallel vector • apply : parallel point-wise application • put: send values • at : projection of a value
Problems with BSP • Global synchronization is too expensive • No hierarchical network capacities • No heterogenelity ICCS 2004 Gava
The MP model MP = messages passing No super-steps but m-steps Proc. 0 1 2 3 Local computing Communication
New model: DMM • We have : • P BSP units • L, latency of the global network • G, time to send one word • List of nb of processes : • List of times for a barrier : • List of times for a 1-relation : • We have d-steps of super-steps ICCS 2004 Gava
New communication BSP Unit i BSP Unit j G et L Intranet g et l i i g et l j j ICCS 2004 Gava
New communication Unit i Unité j g et l i i ICCS 2004 Gava
New language: DMML • Library for the « Objective Caml » language • Operations to access to the DMM parameters • Operations on departmental vectors • mkdpt : creation of a departmental vector • applydpt : departmental point-wise application • get : received values
Conclusion • BSML = BSP + ML • New model for departmental meta-computing • New language called DMML ICCS 2004 Gava
Future Work • Polymorphic type system for the language • Implementation of « big » applications • Static Dependent Costs for Estimating Execution Time ICCS 2004 Gava