Olivier Aumage
Plan • Introduction • computation,clusters, high-performance communications • Framework • PM², RPC, communication interfaces • Proposal • Madeleine 2 • Implementation and evaluation • results on top of TCP, VIA, SCI • Conclusion Olivier Aumage
Introduction • What do academic scientist and industrial engineers need: • complex computations on huge data • high-performance computation machines: clusters of workstations • distributed parallel programming environments for clusters: PM² distributed RPC-based multithreaded environment • efficient communication support suited for such environments Olivier Aumage
RPC • RPC: • Remote Procedure Call • PM² basis paradigm • A communication library for RPC should meet the following requirements: • portability • efficiency • zero-copy data transfer Olivier Aumage
Low Level Interfaces • Characteristics: • direct network access • high efficiency • low portability • Examples: • BIP • Fast-Messages • VIA • SCI Olivier Aumage
High-Level Interfaces: MPI • MPI - Message Passing Interface: • widely used in parallel computation applications • efficient portable implementations:MPI-CH • available on top of BIP and FM • But: • interface is not flexible enough for efficient RPC support Olivier Aumage
Madeleine • Characteristics: • communication library used by PM² • portability • efficiency • dedicated to RPC paradigm • But: • heavily message passing oriented • suboptimal support of recent protocols : SCI, VIA, ... • limited interface Olivier Aumage
Madeleine II Olivier Aumage
User / Madeleine 2 Contract • Interface of Madeleine 2: • semantical specification of data transfer options • Consequences: • semantically adequate with user requirements • more power to the library: • more liberty of movement • more efficiency Olivier Aumage
Example Example of a program using the Madeleine 2 communication library: Sending side : Receiving side : . . . . . . len = strlen("Madeleine 2"); conn = begin_packing(chan, remote); conn = begin_unpacking(chan); pack(conn, &len, sizeof(int), unpack(conn, &len, sizeof(int), send_CHEAPER, receive_EXPRESS); send_CHEAPER, receive_EXPRESS); str = malloc(len + 1); pack(conn, "Madeleine 2", len + 1, unpack(conn, str, len + 1, send_CHEAPER, receive_CHEAPER); send_CHEAPER, receive_CHEAPER); end_packing(conn); end_unpacking(conn); . . . . . . Olivier Aumage
Communication Channels • Multi-channel support: • separate independant communication channels • important for easy modular application development • Multi-protocol support: • one protocol per channel • optimal use of available resources Olivier Aumage
Adaptative Mechanisms • Objective: • support of protocols with multiple paradigms • dynamic paradigm selection for each data block • Solution: • use of a choice functioncriteria: • size • pack/unpack mode • anything else if needed Olivier Aumage
Multi-Paradigm Structure • Connection: • contains one or more links • Link: • symbolizes a given data transfer method • allows full use of protocol dependant characteristics and optimizations • data ordering transparently enforced by Mad2’s high level generic layer • increased efficiency Olivier Aumage
Buffer Management • Two kinds of buffers: • dynamic buffers • static buffers • Responsabilities of the pack function: • allocation of dynamic buffers • static buffer filling • buffers steering to adequate links • buffer group management for burst data transfer Olivier Aumage
Olivier Aumage
Implementation • Features of the implementation of Madeleine 2: • drivers available on top of: • VIA : message passing + RDMA write • SCI : remote write, DMA support planned • TCP • SBP • MPI and BIP support to be ready soon • 100 % operational environment Olivier Aumage
Performance on top of TCP The following tests were realized using 2 PC Pentium II / 450MHz interconnected by a Fast-Ethernet network Olivier Aumage
Performance on top of VIA The following tests were realized using 2 PC Pentium II / 450MHz interconnected by a Fast-Ethernet network Olivier Aumage
Performance on top of SCI The following tests were realized using 2 PC Pentium II / 450MHz interconnected by a SCI network Olivier Aumage
Dynamic Paradigm Selection Olivier Aumage
Conclusion • Madeleine 2 : • more functionalities: multi-channel, multi-protocol, multi-paradigm • increased overall efficiency • full operational system • support for SCI, VIA, TCP, SBP • first high-performance adaptative communication library Olivier Aumage
Future Work Olivier Aumage
Multi-Cluster Support • Objectives : • network-heterogeneous multi-cluster support • metacomputing capabilities • Features : • inter-cluster channel • user-friendly configuration scheme • script-based applications and clusters description • one-step multi-cluster application compilation and launch • support for protocol specific loaders Olivier Aumage
Example Example of cluster and application description files for Madeleine 2 : Cluster description : Application description : cluster popc: application gauss: { { hosts: popc0--11; executable: mad_gauss; domain: popc-private; path: "~/pm2/mad_applis/"; gateways: {domain: ens-lyon; host: popc0;}; clusters: adapters: {name: popc; hosts: popc0--3;}, {alias: TCP0; protocol: tcp;}, {name: sci; hosts: sci0--4;}; {alias: TCP1; protocol: tcp; suffix: "-t";}, channels: {alias: BIP; protocol: bip;}; {alias: Control; } adapter: sci.TCP0, popc.TCP0;}, {alias: Calc; adapter: sci.SCI, popc.BIP;}; } Olivier Aumage
Clusters of cluster : • dynamic protocol selection • multi-protocol routing • architecture and network heterogeneity support Computation/communication scheduling : • optimized communication management • multiple reception policies support Olivier Aumage
