Malleability, Migration and Replication
for Adaptive Distributed Computing over Dynamic Environments

Boleslaw Szymanski, 
Center for Pervasive Computing and Networking
Rensselaer Polytechnic Institute, Troy, NY, USA

Modern parallel execution environments, from grids to volunteered computing
resources (e.g., using BOINC), dynamically change over time. Hence,
long-lasting parallel computations should adapt autonomously to the available
resources. The key to such adaptability is the system ability to support
malleability, migration and fault tolerance of application processes. This
talk defines these concepts and discusses how they are implemented in the
Internet Operating System (IOS), a middleware system that supports dynamic
parallel execution. We will also discuss ramifications of different features
of the programming languages required for middleware and application
implementation.

Malleability enables a parallel execution system to split or merge processes
of a parallel application to modify its granularity. Current support for
process migration is limited by the granularity of the application's processes
and malleability removes this limitation. We have implemented malleability as
an extension to the PCM (Process Checkpointing and Migration) library, a
user-level library for iterative MPI applications. PCM is integrated with IOS,
a framework for middleware-driven dynamic application reconfiguration written
in the SALSA actor programming language. Our approach requires minimal code
modifications and enables transparent middleware triggered reconfiguration.
The talk will present experimental results that demonstrate the usefulness of
malleability and will also outline our future work in this area.

About the speaker: Dr. Boleslaw K. Szymanski is the Claire and Roland Schmitt
Distinguished Professor at the Department of Computer Science and the Founding
Director of the Center for Pervasive Computing and Networking, Rensselaer
Polytechnic Institute. He received his Ph.D. in Computer Science from National
Academy of Sciences in Warsaw, Poland, in 1976. He was a post-doctoral fellow
at the Aberdeen University in Scotland and on the faculty at the University of
Pennsylvania. Dr. Szymanski is an IEEE Fellow. His interests cover the broad
area of distributed and parallel computer systems and algorithms with emphasis
on sensor networks.