![](bg6.png)
Threads can be used to simplify the structure of
complex, server-type applications. Simple routines
can be written for each activity (thread), making
complex programs easier to design and code, and
more adaptive to a wide variation in user demands.
This has further advantages in the maintainability of
the application and future extensions.
The multithreaded paradigm can also improve
server responsiveness. Complex requests or slow
clients do not block other requests for service, the
overall throughput of the server being increased.
4 CONCLUSIONS
We have presented here our extended master-worker
model, which has been used in the QADPZ
development. Our model includes some refined
capabilities that are meant to increase the
performance and efficiency of the computation: push
of work units, pipelining, sending more work-units
at a time, adaptive number of workers, adaptive
timeout interval for work units, and use of
multithreading. Further measurements need to be
made in order to sustain our preliminary benchmark
tests that suggest significant improvements
regarding efficiency of the computation.
REFERNCES
Berman, F., et al., 2003. Grid computing: making the
global infrastructure a reality, J. Wiley, New York
BOINC. (2006) Open Source Software for Volunteer
Computing and Grid Computing (online) Available
from http://boinc.berkeley.edu, (Accessed 25
November 2007)
Constantinescu, Z., 2003 Towards an autonomic
distributed computing environment, in Proceedings of
14
th
International Workshop on Autonomic Computing
Systems, held in conjunction with 14
th
Int. Conf. on
Database and Expert Systems Applications DEXA
2003, pp. 694-698, Prague, Czech Republic
Constantinescu, Z. & Petrovic, P., 2002, Q2ADPZ* an
open source, multi-platform system for distributed
computing. ACM Crossroads, 9, pp. 13-20.
Constantinescu, Z., 2008, A desktop grid computing
approach for Scientific Computing and Visualization,
PhD Thesis, Norwegian University of Science and
Technology, Trondheim, Norway
Cummings, M. P., (2007), Grid Computing (online)
Available from http://serine.umiacs.umd.edu/
research/grid.php (Accessed 25 March 2008)
David, P. A., et. al., 2002 SETI@home: an experiment in
public-resource computing. Communications, ACM,
45, pp. 56-61.
Distributed.Net (2008) (online) Available from
http://distributed.net, (Accessed 5 March 2008).
Distributedcomputing.Info (2008) (online) Available from
http://distributedcomputing.info, (Accessed 5 March
2008)
Foster, I. & Kesselman, C., 1999. The grid: blueprint for a
new computing infrastructure, San Francisco, Morgan
Kaufmann Publishers.
Foster, I. & Kesselman, C., 2004. The grid: blueprint for a
new computing infrastructure, Amsterdam, Boston,
Morgan Kaufmann.
Garg, V. K., 1996. Principles of distributed systems,
Boston, Kluwer Academic Publishers.
Garg, V. K., 2002. Elements of distributed computing,
New York, Wiley-Interscience.
Globus (2007) Globus (online) Available from http://
www.globus.org, (Accessed 15 March 2008)
Juhasz Z., Kacsuk P., Kranzlmuller D., 2004, Distributed
and Parallel Systems: Cluster and Grid Computing,
New York, Springer
Karniadakis, G. & Kirby, R. M., 2003. Parallel scientific
computing in C++ and MPI: a seamless approach to
parallel algorithms and their implementation, NY,
Cambridge University Press.
Leopold, C., 2001. Parallel and distributed computing: a
survey of models, paradigms, and approaches, New
York, Wiley.
Mustafee, N. & Taylor, S. J. E., 2006. Using a desktop
grid to support simulation modelling, in Proceedings
of 28th International Conference on Information
Technology Interfaces (ITI 2006), Dubrovnik, Croatia,
pp. 557 - 562
QADPZ (2008) (online) Available from http://
qadpz.sourceforge.net. (Acc. 1 April 2008).
SETI@HOME (2003) (online) Available from http://
setiathome.ssl.berkeley.edu, (Acc5 May 2003)
SOURCEFORGE (2008) (online) Available from http://
sourceforge.net, Acc 1 April 2008
Sunderam, V. S., 1990 PVM: a framework for parallel
distributed computing. Concurrency: Practice.
Experience, Vol. 2, pp 315-339.
Vahid, G., Lionel, C. B., Yvan, L., 2006 Traffic-aware
stress testing of distributed systems based on UML
models, in Proceeding of the 28th International
Conference on Software engineering, Shanghai, China
Zomaya, A. Y., 1996
Parallel and distributed computing
handbook, New York, McGraw-Hill.
ICSOFT 2008 - International Conference on Software and Data Technologies
174