call for participation: Virtual Shared Memory Symposium
Tom Franklin
Last call for participation in
Virtual Shared Memory Symposium
===============================
to be held at
The Centre for Novel Computing
The University of Manchester
England
on
17th and 18th September
In Conjunction with
SERC - NACC
and
BCS - PPSG
Contents:
Symposium timetable
biographies of speakers and abstracts of talks
applications details
Virtual Shared Memory Symposium
17th and 18th September
Programme
Thursday 17 September
9:00 - 10:00 Registration
10:00 - 10:15 Welcome by John Gurd, CNC
10:15 - 11:05 Nic Holt, ICL
Virtual Shared Memory in Commercial Applications
11:05 - 11:30 Tea and coffee
11:30 - 12:30 Vadim Abrossimov, Chorus Systemes
Distributed Virtual Memory in Chorus
12:30 - 13:30 Lunch
13:30 - 14:30 Steve Frank, KSR
Memory System Architecture and Programming
Environment of the KSR1
14:30 - 15:15 Peter Bird, ACRI
Proactive Systems
15:15 - 16:00 Tea and coffee
16:00 - 17:00 William Jalby, University of RENNES
Replacement Policies For Hierarchical Memory Systems
17:00 - 18:00 Chris Wadsworth
VSM: The Good, The Bad and The Unknown
Friday 18 September
9:30 - 10:20 Clemens-August Thole, GMD
High Performance Fortran and its Relevance for VSM
Architectures
10:20 - 11:10 Mike Delves, University of Liverpool
Development of an HPF-Conformant Parallel Fortran90
Compiler
11:10 - 11:40 Tea and coffee
11:40 - 12:30 Sven Hammarling, NAg
The development of a Numerical Software Library for
Parallel Machines
12:30 - 13:30 Lunch
13:30 - 14:20 Iain Duff, Rutherford Appleton Laboratory
The Solution of Sparse Systems on Parallel Computers
14:20 - 15:10 Harry Wijshoff, University of Leiden
Implementation issues of Sparse Computations
15:10 - 15:50 Tea and coffee
15:50 - 16:40 David Culler, University of California at Berkeley
Active Messages: a Fast, Universal Communication
Mechanism
16:40 - 17:00 Closing Address - John Gurd, CNC
Virtual Shared Memory Symposium
Speakers and Abstracts:
Professor Nic Holt
==================
Virtual Shared Memory in Commercial Applications
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Nic Holt is a System Designer at ICL and was responsible for the primitive
architecture of the ICL Series 39 which features processing nodes
interconnected by Optical Fibre, providing Virtual Shared Memory for
commercial applications.
Abstract
The ICL Series 39 system, originally designed in 1982, has an architecture
in which multiple processors each with closely coupled memory, known as
"processing nodes", are interconnected by an optical fibre network. Series
39 supports Virtual Shared Memory by a technique known as Replicated
Storage: pages of virtual memory may be replicated across multiple nodes.
Hardware mechanisms in each node generate protocol on the network to
propagate memory updates and provide a basic synchronisation mechanism
between the nodes. The system architecture and a number of existing
commercial applications will be described in detail. The VSM facilities of
the EDS machine, a distributed memory parallel processor will also be
mentioned. The characteristics of various shared memory schemes and their
use by applications will be discussed.
Vadim Abrossimov
================
Distributed Virtual Shared Memory in Chorus
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Vadim Abrossimov is one of the key architects of the Chorus micro-kernel.
He concentrated on the design and implementation of the CHORUS distributed
Virtual Memory Management.
He joined Chorus Systemes at its creation in 1986 after spending two years
at INRIA working on object oriented systems.
Abstract
Many high-end open systems under development today are characterized by the
innovative use of multiple processors in distributed memory configurations
("multicomputers"). These parallel processors provide wider I/O throughput
for mainframe-power UNIX systems, redundancy for reliable OLTP systems and
enormous computation power for massively parallel supercomputer systems.
To master these more complicated environments and get these more
complicated machines to market faster, system builders need an operating
system development environment that is as powerful as the development
environment provided to applications builders by UNIX.
Modern operating systems have to meet certain design objectives to meet
these requirements and support the inherent distributed environment of
high-end systems. And they must do this while providing complete BCS/ABI
compatibility with UNIX and Open Systems standards.
One approach to modern operating system design is to build the distributed
operating system as a set of independent system servers using the
primitive, generic services of a micro-kernel. The micro-kernel provides a
virtual machine for processor use, memory allocation and communication
between operating system components.
To provide scalability and portability, a modern operating system should
offer complete support for portability not only over a range of processors,
but also over a range of hardware system-level architectures. It should
also offer transparent re-usability of system components, modularity,
scalability of hardware configurations and system services, and structured
integration of device drivers and specific hardware features. To enable
system services, a modern operating system should provide transparent
distribution of services, fault tolerance, security, performance
flexibility and full compatibility with standard operating system
interfaces.
The presentation outlines how a modern micro-kernel based operating system
architecture such as CHORUS can meet these needs, in particular by looking
at how it provides virtually shared memory over distributed configurations.
Steve Frank
===========
Memory System Architecture and Programming Environment of the KSR1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Mr. Frank is a co-founder of Kendall Square Research and made a major
contribution to the architecture, design partitioning, and technology
selection of the KSR1. He is presently involved in the definition of future
products. Prior to joining KSR, he contributed to the architecture and
implementation of three multiprocessors: Encore's MultiMax, the Synapse N+1
and a multiprocessor for an experimental PBX at Rolm. Mr. Frank earned his
B.S. and M.S. degrees in Electrical Engineering from the Massachusetts
Institute of Technology.
Abstract
The KSR1 is the first highly parallel computer system that unites the power
of parallel processing with a conventional shared memory software
development environment to satisfy the production requirements of both the
commercial and technical applications. Shared memory is achieved through a
technique called ALLCACHE memory. This mechanism, implemented in hardware,
builds the abstraction of shared memory on a set of distributed memory
units which are managed as coherent caches. The underlying hardware also
includes a full 64 bit superscalar processor.
The talk will start by discussing related research which led to the
development of the KSR1. The KSR1 programming environment and ALLCACHE
memory architecture will be presented as a context to describe key
architecture and implementation issues.
Peter Bird
==========
Proactive Systems
~~~~~~~~~~~~~~~~~
Biography
Peter Bird received his PhD in Computer Science from the University of
Michigan. He studied retargetable, pattern directed code generators which
optimised pipeline scheduling.
He designed and developed compilers for a parallel pipelined machine for a
data-flow specification language for ODEs used for Real-Time applications.
Currently He is computer system architect for ACRI in Lyon, France, where a
multi-nodal, high performance system is being developed.
Abstract
not available yet
William Jalby
=============
Replacement Policies For Hierarchical Memory Systems
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
William Jalby began his career as a researcher at INRIA, then spent 18
months at University of Illinois (Center for Supercomputing Research and
Development) and in 1988 was appointed as a professor of Computer Science
at the University of Rennes. His research interests mainly concern memory
organization (architecture, software and performance evaluation). He is the
vice chairman of the ESPRIT BRA APPARC project.
Abstract
One of the key components in determining the performance of a hierarchical
memory system is the strategy used for replacing pages (blocks). In the
general case (i.e. without any specific knowledge on the memory reference
pattern), simple heuristics like LRU (Least Recently Used) exhibit
relatively good behaviour. On the other hand, if the entire memory pattern
is known a priori, an optimal replacement strategy can be used (Belady's
MIN algorithm). In this talk, the old problem of replacement strategies is
revisited but focusing on regular loop structures such as those arising in
many numerical codes. In such cases, memory reference patterns can be
determined at compile time and can be used to derive efficient replacement
policies. After noting that LRU can exhibit pathological behaviour for such
loop structures, we analyse in detail the behaviour of Belady's algorithm.
In particular, for some simple cases, its (optimal) hit ratio is computed
as well as its impact on array management. Finally, we describe some simple
heuristics that achieve hit ratios close to optimal.
Dr. C P Wadsworth
=================
Virtual Shared Memory: The Good, The Bad, and The Unknown
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Dr. Chris Wadsworth is leader of the Parallel Processing Group in the
Informatics Department at RAL, with projects in the systems aspects and
techniques of parallel programming and the porting of applications
software. The Group also takes a leading role in projects for Oxford
Parallel, a joint centre with Oxford University under the DTI/SERC Parallel
Applications Programme. His present interests focus on the exploitation of
parallelism, the requirements for portable parallel software, and high
level performance models for parallel machines.
Abstract
An overview of the advantages, disadvantages, and challenges of virtual
shared memory computing will be presented. While the main benefits are
readily appreciated, it is argued that particular challenges remain in the
evolution of higher-level programming concepts. The role of sharing -- when
to share, and how to do so safely -- in parallel program designs will be a
particular topic for discussion.
Clemens-August Thole
====================
High Performance Fortran and its relevance for VSM architectures
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Clemens-August Thole has worked in the field of programming models and
applications for distributed memory architectures since 1984. He was
project manager of the Esprit GENESIS project, which aimed for a
programming environment for parallel architectures. He is currently
employed by the Gesellschaft fuer Mathematik und Datenverarbeitung (GMD),
St. Augustin, Germany, member of the core group of the High Performance
Fortran Forum and chairman of the related European working group.
abstract
A virtual shared memory programming model for a parallel architecture makes
the port of programs simpler. The limited speed of interconnection networks
and clustering of the address space into pages and subpages requires
detailed consideration of the mapping of the data structures onto the
address space, the tiling of loops and the distribution of threads onto the
processors.
High Performance Fortran (HPF) as is currently being defined by the HPF
Forum allows the application programmer to specify the mapping of data
objects and statements to processors by compiler directives.
The presentation gives an introduction to HPF and outlines the possibility
for exploitation of this information by compilers of virtual shared memory
architectures.
Mike Delves
===========
Development of an HPF-Conformant Parallel Fortran90 Compiler
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Professor Delves has held the Chair of Computational Mathematics at the
University of Liverpool since 1969. He is Director of the Centre for
Mathematical Software Research, and the Transputer Support Centre, both
self-supporting Research Centres within the University specialising in
scientific/engineering parallel computing. His interests in computational
mathematics include Parallel Algorithms, Integral and Partial Differential
Equations and the Seising of High Level Scientific Languages.
He is a member of ADA Europe and the Ada Numerics Task Force; and a founder
member of the Esprit SIG on Parallel Languages for Scientific Computing,
which currently provides a European forum for interacting with the US HPF
initiative.He has published over 170 papers, is author of two books on
numerical algorithms, and editor of four others.
Abstract
The High Performance Fortran (HPF) proposals provide a shared-memory style
of programming in Fortran90 with the ability for the user to input
sufficient help for compilers; the language plus directives supports data
parallel SIMD programs. With NA Software and with input from Inmos, we are
developing a compiler for an extended Fortran90 language; the code
includes:
o Full Fortran90;
o HPF Directives;
o MIMD syntax extensions.
The work is taking place within the Esprit Supernode II and PPPE projects;
target dates for the first compiler release are April 1993 for parallel
Fortran90; end 1993 for HPF support. This paper gives details of the design
of the language and compiler, and a summary of progress with it's
development.
Mr. Sven Hammarling
===================
Development of Portable Numerical Software for Parallel Machines
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Sven Hammarling is currently the Manager of the Numerical Libraries
Division at the Numerical Algorithms Group in Oxford. He is one of the
authors of the Level 2 and Level 3 Basic Linear Algebra Subprograms (BLAS),
is involved in the LAPACK project, which has been developing a linear
algebra package for high-performance computers and is Workpackage Manager
for the Libraries Workpackage on the ESPRIT II project, Supernode II.
Abstract
NAG has always aimed to to make their library available on any type of
computer for which there is reasonable demand for it, which in practice
means any computer in widespread use for general purpose scientific
computing. The NAG Fortran Library is currently available on more than
fifty different machine ranges, and on somthing like a hundred different
compiler versions. Thus portability of the library has always been a prime
consideration. The advent of vector and parallel computers has required us
to pay much more careful attention to the performance of the library, and
the challenge has been to try satisfy the sometimes conflicting
requirements of performance and portability.
We shall discuss how we have approached the development of library software
for modern high-performance machines, concentrating in particular on our
involvement in the LAPACK project which has been developing a linear
algebra package.
The features of modern machines that have to be utilized to achieve
efficiency include vector registers or pipelines, multiple processors and a
hierarchy of memory. To retain portability in LAPACK, efficiency is
achieved principally through the use of the Basic Linear Algebra
Subprograms (BLAS), the matrix-vector operations of the Level~2 BLAS for
single processor, non-hierarchical memory vector machines and the
matrix-matrix operations of the Level~3 BLAS otherwise. In the case of the
Level~2 BLAS this has meant restructuring the algorithms to clearly expose
the matrix-vector nature of the operations, and in the case of the Level~3
BLAS has necessitated the design of block algorithms to yield matrix-matrix
operations.
We shall also consider the impact of Fortran 90, which has recently become
an ISO standard, on library development, particularly the use of the array
features for expressing parallelism.
Iain Duff
=========
The Solution of Sparse Systems on Parallel Computers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Iain S Duff is Group Leader of Numerical Analysis in the Central Computing
Department at the Rutherford Appleton Laboratory. He is also project Leader
of the Parallel Algorithms Group at CERFACS in Toulouse and is a visiting
Professor of Mathematics The University of Strathclyde. Duff obtained a BSc
from the University of Glasgow where he held an IBM Scholarship. He was
Carnegie Fellow at Oxford, completed his diploma in Advanced Mathematics in
1970, and received his D Phil on "Analysis of Sparse Systems" from the
University of Oxford in 1972. He then was Harkness Fellow visiting Stony
Brook and Stanford and thereafter spent two years as a lecturer in Computer
Science at the University of Newcastle before joining the Numerical
Analysis Group at Harwell in 1975. He moved to his present position in June
1990.
He has had several extended visits to Argonne National Laboratory, the
Australian National university, the University of Colorado at Boulder,
Stanford university, and the University of Umea.
His principal research interests lie in sparse matrices and vector and
parallel computing. He has also been involved for many years in the
development and support of mathematical software, particularly through the
Harwell Subroutine Library. He has published over 100 papers, has
co-authored two books, and has been editor or joint-editor of several
conference proceedings. He is editor of the IMA Journal of Numerical
Analysis and associate editor of several other journals in numerical
analysis and advanced scientific computing. He is a fellow of the Institute
of Mathematics and its Applications, and a member of SIAM, SMAI and SBMAC.
Abstract
The multifrontal technique solves systems of sparse linear equations using
Gaussian elimination and exploits parallelism both through sparsity via an
elimination tree (a computational graph) and through use of Level 3 Basic
Linear Algebra Subprograms.
We briefly describe multifrontal methods and illustrate the benefits of
parallelism from these two sources by examining the performance of
multifrontal codes on a range of shared memory architectures. More recently
we have examined the performance of our codes on the BBN TC 2000, a virtual
shared memory machine. We show that, although a fairly straightforward
adaptation of the shared memory code will, as expected, run on the TC 2000,
design changes which recognize data locality yield a significantly improved
performance. We feel that the issues we raise are important for any virtual
shared memory environment and that the architecture must still be
understood if high performance is to be obtained.
Finally we indicate one way in which our techniques can be extended to
distributed memory architectures or networks of workstations.
H.A.G. Wijshoff
===============
Implementation Issues of Sparse Computations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
Professor Harry A.G. Wijshoff has been appointed as a full professor in
computer systems and software at the University of Leiden since July 1,
1992. Previously he worked at University of Illinois, RIACS, NASA Ames, and
Utrecht University. At the University of Leiden he is the leader of a group
of 12 scientist in the area of high performance computing and parallel
processing. He is the coordinator of a recently awarded Esprit III BRA
project on Performance critical applications of parallel architectures
(APPARC). His current research interests cover parallel architectures,
sparse matrix computations, programming environments and performance
evaluation.
Abstract
In this talk the intrinsic complexity of sparse computations will be
addressed together with consequences of providing architectural support for
these computations. Sparse computations will be a major challenge for
shared virtual memory implementations as they do not lean themselves easily
for exploiting data locality. Ways of overcoming this bottleneck will be
discussed.
David E. Culler
===============
Active Messages: a fast, universal communication mechanism
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Biography
David Culler is an Assistant Professor in the Computer Science Division of
the University of California at Berkeley and a Presidential Faculty Fellow.
His research interests include computer architecture, resource management,
and the implementation of a wide range of parallel programming models,
including dataflow, functional programming, hardware description languages,
and explicit distributed memory.
Abstract
Multiprocessor architectures are traditionally divided into three
categories based on their intended programming model: shared memory,
message passing, and "novel". The last is a euphemism for dataflow,
reduction, and the like. However, careful study reveals that the
implementations of these apparently diverse architectures are surprisingly
similar. Active Messages is a simple communication primitive that captures
this common element. The implementation of Active Messages on current
message passing machines (CM-5 and nCUBE/2) is an order of magnitude faster
than the send/receive model for which the machines were designed. The
universality of the mechanism has been demonstrated by realizations of
shared memory, message passing, and dataflow models on the same machine. In
addition, a variety of hybrid models have been developed, including a
split-phase global memory extension to C, called Split-C. The goal of this
work is to define better architectural primitives for communication, rather
than to build new abstractions on top of existing inefficient primitives.
Who Should Attend
=================
The symposium is aimed at all people working in the area of parallel
computing. It will provide a detailed introduction to Virtual Shared Memory
and current research issues.
It will be of particular interest to developers of applications, whether
numeric, symbolic or database applications, who need power of parallel
computing, but have been put off in the past by the difficulties of
parallel computing.
The symposium will also be of interest to systems implementors and
architects working on parallel systems.
Venue
=====
The Symposium will be held at the Department of Computer Science, Computer
Building, University of Manchester. The department has access and
facilities for disabled visitors.
Catering and Accommodation
==========================
Every effort will be made to cater for special dietary requirements if
details are provided with the completed application forms.
Accommodation is provided in Hulme Hall, one of the University's halls of
residence about 15 minutes walk, or a short bus ride from the department.
Accommodation can only be provided if the form is returned by 9 September.
_________________________________________________________________________
Application Form
To: Ursula Hayes
Department of Computer Science
University of Manchester
Manchester
M13 9PL
England
Telephone: +44 (61) 275 6172
Fax: +44 (61) 275 6236
email v...@cs.man.ac.uk
Title _________ Forename _______________________________
Surname _____________________________________________________
Address _____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
Postcode _____________________________________________________
Telephone _____________________________________________________
Fax _____________________________________________________
email _____________________________________________________
The fee includes the Symposium fee and proceedings,
lunches and coffee.
Fee: Full 200.00
BCS PPSG 180.00
Academic 100.00
Nights in Hulme Hall @ 20.00:
Wednesday 16th __
Thursday 17th
Friday 18th __
Enclosed fee ____________
Dietary Requirements: _________________________________________
Please make Cheques payable to "The University of Manchester"
_________________________________________________________________________
--
Tom.
Tom Franklin
Centre for Novel Computing Phone +44 61 275 6134
Department of Computer Science Fax +44 61 275 6204
University of Manchester
Manchester email to...@cs.man.ac.uk
M13 9PL
=================================================================