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Protocols and software for exploiting Myrinet clusters Congduc Pham and the main contributors P. Geoffray, L. Prylli, B. Tourancheau, R. Westrelin.

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Presentation on theme: "Protocols and software for exploiting Myrinet clusters Congduc Pham and the main contributors P. Geoffray, L. Prylli, B. Tourancheau, R. Westrelin."— Presentation transcript:

1 Protocols and software for exploiting Myrinet clusters Congduc Pham and the main contributors P. Geoffray, L. Prylli, B. Tourancheau, R. Westrelin

2 Parallel machines and clusters Cplant Standalone workstation

3 Pros for clusters n Large supercomputers are expensive and suffer from a short useful life span n Performance of workstations and PCs is rapidly improving n The communications bandwidth between workstations is increasing as new networking technologies and protocols are implemented in LANs and WANs. n Workstation clusters are easier to integrate into existing networks than special parallel computers. n Use of clusters of workstations as a distributed computing resource is very cost effective - incremental growth or update of system!!!

4 No polemical discussion, just statement… Mainframe Vector Supercomputer Mini Computer Workstation PC 1984 from R. Buyya GigaEthernet Giganet SCI Myrinet …

5 The Myrinet technology n Switch –full crossbar –wormhole source routing –small latency n Network interface –embedded RISC processor –programmable –local memory –several DMA engines Current specifications: Up to 200Mhz processor Up to 8MB local memory 64bit/66Mhz PCI bus (528 MB/s peak) 250 MB/s full duplex links

6 The raw performance is here, but… n the traditional communication software fail to bring the hardware performance to the applications Myrinet Traditional communication layers Optimized communication layers 200mph40mph 180mph 35mph 175mph

7 Going faster by taking shortcuts

8 Our communication architecture n Provides a complete suite for high-performance communications.Focus on Myrinet-based clusters n Viewed as layers, but by-passes as much as possible the OS Myrinet physical layer BIP BIP-SMP MPI-BIP programmable NICs break the traditional spatial distribution of tasks

9 BIP, the lowest protocol level n Basic Interface for Parallelism –very basic API –provides a library, a kernel module and a MCP –definitely not for the end-user n Optimizations for –latency –maximum throughput –the throughput increase n The implementation performs –reduction of the data critical path –distinction between small and large messages –burst or write combining for host  NIC –optimal cache usage –cache snooping for NIC  host (monitoring of the PCI bus) –buffer alignment –optimal fragment size… Myrinet BIP BIP-SMP MPI-BIP

10 n Avoids handshakes between the host and the NIC n Uses PIO to a NIC FIFO on the sending side and an extra memory copy on the receiving side BIP, small message strategy

11 n Use DMA both on the send side and receive side: higher bandwidth, offload the CPU n Zero-copy mechanism, pipelined transmission BIP, large message strategy

12 BIP-SMP: a low level for SMP machines n SMP viewed as best performance/price ratio architectures (2 or 4 proc.) n BIP-SMP provides –manage concurrent accesses to the NIC –low latency intra-node communications –BIP equivalent inter-node communication –total transparency for the applications and end-users

13 BIP-SMP: Moving data between processes

14 MPI-BIP: the communication middleware n MPI-BIP adds high-level features to BIP –based on the MPICH implementation –provides a portable and widely-used API –implements a credit-based flow control for small messages –request FIFO for multiple non-blocking operations –provides segmentation/reassembly features to avoid timeouts

15 Working with the BIP software suite n installation –run configure n compilation and linkage –several libraries: bip, bip-smp, mpi –compile with bipcc n Submitting jobs and monitoring nodes –run myristat to know which nodes are available –run bipconf to configure the virtual machine –use bipload to lunch programs

16 WebCM: a high level management tool n web-based management tool n integrates existing solutions into a common framework

17 The WebCM user interface graphical interface for myristat and bipconf n allows submission of jobs through batch packages n shows the user's virtual machine definition and the user's runnning processes n addition of fonctionnalities is performed by incorporating new software packages

18 Latency: BIP and MPI-BIP

19 Throughput: BIP and MPI-BIP

20 BIP-SMP: intra-node communications

21 BIP-SMP: inter-node communications

22 What run on our clusters? n Genomic simulation n Fluid dynamic n Discrete Event Parallel Simulation n Distributed Shared Memory System n Want to know more? –getting the distribution –getting the documentation


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