3.2.2 GpH -- Glasgow Parallel Haskell

Report by: Phil Trinder

The Team:

Phil Trinder, Kevin Hammond, Hans-Wolfgang Loidl, Abyd Al Zain, Jost Berthold, Murray Gross, Andre Rauber du Bois, Alvaro Rebon Portillo, Leonid Timochouk.

Status:

A complete, GHC-based implementation of the parallel Haskell extension GpH and of evaluation strategies is available. Extensions of the runtime-system and language modules, to improve performance and support for architecture-independence, are under development.

Implementations:

The GUM implementation of GpH is available in two development branches.

The stable branch (GUM-4.06.2, based on GHC-4.06) is available for RedHat-based Linux machines: as source bundle and as a binary snapshot for RedHat 8.0. A slightly older version GUM-4.06 is available as source bundle or binary snapshot for RedHat 7.0 Intel Linux (libc2.1). See installation instructions. The stable branch is available from the GHC CVS repository via tag gum-4-06.
The unstable branch (GUM-5.02, based on GHC-5.02) is currently being tested on a Beowulf cluster. Most of our test programs run already, with minor issues left to be resolved before this version will become our main development version. The unstable branch is available from the GHC CVS repository via tag gum-5-02-3.

Our main hardware platform are Intel-based Beowulf clusters. Work on ports to other architectures is also moving on (and available on request):

A port to a Sun-Solaris shared-memory machine exists but currently suffers from performance problems, which we are trying to track down.
A port to an SGI-Irix multi-processor is underway at Universidad Complutense de Madrid.
A port to a Mosix cluster is being built in the Metis project at Brooklyn College (section 6.4.3), with a first version available on request from Murray Gross.

System Evaluation and Enhancement:

We have undertaken a comparison of implementation designs for parallel functional languages (http://www.macs.hw.ac.uk/~dsg/gph/papers/drafts/ppdp.ps.gz), specifically GUM implementation of GpH with the Skeleton-based parallel ML implementation PMLS (http://www.cee.hw.ac.uk/Research/funct_prog.html)
We have evaluated the effect of introducing thread migration (http://www.macs.hw.ac.uk/~dsg/gph/papers/ps/Migration-IFL02.ps.gz) in GUM (IFL02).
We are currently investigating the challenges posed by porting GUM to a computational GRID, replacing the current PVM layer with IMPICH-G2.
We are starting to investigate engineering a combined, modular Eden (section 3.2.4)/GpH implementation

GpH Applications:

A new EPSRC project (GR/R91298) has just started at St Andrews University to investigate providing parallel implementations of the GAP group algebra libraries using GpH.
We have investigated the architecture independence (http://www.macs.hw.ac.uk/~dsg/gph/papers/drafts/hlpp03.ps.gz) of GpH by measuring a significant application (genetic alignment) on two very different architectures: a Beowulf cluster, a SunServer SMP.

Language:

We are constructing efficient implementations of algorithmic skeletons in GdH, and plan to experiment with their use, in conjunction with evaluation strategies.

3.2.2.1 Further reading:

http://www.macs.hw.ac.uk/~dsg/gph/

<gph@macs.hw.ac.uk>

http://www.macs.hw.ac.uk/~dsg/gph/papers/abstracts/strategies.html