17.op/CVR.vaduvur
.m From bharghav@genesis-a.CS.Berkeley.EDU Wed Sep  1 13:07:58 1993
.ls 2
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Low Overhead Distributed Discrete-Event Simulation System

Bharghavan Vaduvur

(Professor C. V. Ramamoorthy)

We have designed and implemented Empathy [1], a distributed
discrete-event simulation system using optimistic processing of events
and locally conservative commitment of events.

Our first prototype could only simulate applications in which the
communication topology was static. The experience and performance of
this simulator was reported in [2]. We then designed a hierarchical
commitment algorithm that enabled us to simulate applications with both
static and dynamically changing communication topology. We provided
application-dependent rollback schemes. The second prototype and its
performance are described in [3].

We have designed and implemented a super-simulator layer on top of
Empathy, which is expected to provide significant speedup when
simulating a set of applications with similar communication topology.
This layer takes as its input a set of design choices and performance
criteria, then provides the best design choice. We are now studying the
performance of the super-simulator. Empathy is currently being used in
our lab to simulate applications ranging from cooperative reasoning to
metrics analysis. Further work will be directed in the area of user
interface and fine tuning the performance.

[1]	V. Bharghavan and C. V. Ramamoorthy, "Design and Implementation of Empathy:   A Distributed Discrete-Event Simulation System," Proc. Int. 
Conf. Parallel and Distributed Systems, 
1993 (to be published).

[2]	V. Bharghavan and C. V. Ramamoorthy, "Overhead Reduction in Distributed
Simulation," Int. Symp. Autonomous Decentralized Systems, Kawasaki, Japan, 1993.

[3]	V. Bharghavan and C. V. Ramamoorthy, "Efficient Commitment of Events in
Distributed Simulation," Comp. Software and Applications
Conf., 1993 (to be published).