Williams

1
A Linux-based Software Environment for the
Reconfigurable Scalable Computing Project

• John A. Williams1 (jwilliams_at_itee.uq.edu.au)
• Neil W. Bergmann1 (n.bergmann_at_itee.uq.edu.au)
• Robert F. Hodson2 (robert.f.hodson_at_nasa.gov)
• 1 The University Of Queensland, Australia
• 2 NASA Langley Research Center

2
RSC Platform Architectural Overview

• Collection of one or more modular stacks of
  computing elements
• RPM is core reconfigurable component hosting
  reconfigurable FPGA fabric

3
RSC Embedded Processing

• Primary target microprocessor is the MicroBlazeTM
  soft processor.
• Design mitigated with XTMR tool (or manually)
• Embedded Linux
• No MMU -gt uClinux
• Provides easy path to high level development for
  instrument applications (C, sockets, file
  systems, etc)
• Development environment similar (if not
  identical) to typical Linux desktop

4
RSC Software Environment

• Why Linux?
• Path for existing applications onto RSC
• Standard platform improves design efficiency
• Application development/debug
• Multiprocessing/clustering
• Software infrastructure
• Interoperability
• Networking
• File systems
• Desktop application prototyping
• Linux is the C runtime D. Jeff Dionne

5
Software Multiprocessing Model

• Message Passing Interface (MPI, MPI2)
• Standardised protocol for message passing
  parallel computation
• Strong uptake in terrestrial cluster computing
  community
• Supports distributed (networked) clusters as well
  as shared memory machines
• MPI on MicroBlaze and uClinux
• Based on Argonne National Labs MPICH2
  implementation
• Start with MPICH on Linux TCP/IP stack
• Migrate to higher performance implementation as
  RSC network architecture evolves

6
Hardware Multiprocessing Model

• Reconfigurable Processing Module (RPM)
• Application FPGA logic capacity (after TMR)
• Two CPUs, support HW, system interconnect
• Custom processing HW and IO cores
• 512MB shared EDAC DRAM
• Multiprocessing options
• SMP Linux
• Dual UP Linux (shared memory)
• UP Linux custom coprocessor
• UP Linux I/O processor

7
Hardware Multiprocessing Model
Application FPGA (Xilinx)
CPU0
CPU1
Timer / INTC/
Caches
Timer / INTC/
Bus I/F
On-Chip Peripheral Bus
On-Chip Peripheral Bus
I/O core(s)
I/O core(s)
Custom core
Custom core
Custom core
Custom core
SLiP I/F
Interface FPGA (Actel)
On Chip Bus (Wishbone)
PCI I/F
3.3V PCI 33MHz 32/64 bit
8
Status and outlook

• OS and multiprocessing prototyping
• COTS FPGA eval board
• Insight-Memec V4LX25 comms module
• Dual ethernet, uart
• 64MB DDR
• UP Linux reference design completed
• SMP feasibility study underway
• Dual UP Linux
• Dual MicroBlaze HW system built
• Dual kernel bringup underway
• MPICH2 port in progress
• MPICH libraries integrated into uClinux build
• Preliminary port of cluster process manager
  daemon

9
Status and outlook

• COTS prototype cluster
• 4 x dual CPU subsystems

10
Research questions

• Impact of TMR on performance
• How to represent custom HW in an MPI cluster
• Coprocessor to CPU nodes?
• Fully fledged MPI nodes / peers?
• Application of standard Linux technologies for
  reliability and survivability
• RAID ramdisks
• Cluster node failover
• Performance modeling and analysis
• Rob Jones, RSC Co-I