Grid Entities

All the **Grid Entities** in The Binding of Isaac Genesis+

== GridSim entities
GridSim supports entities for simulation of single processor and multiprocessor, heterogeneous
resources that can be configured as time- or space-shared systems. It allows setting of the clock to
different time zones to simulate geographic distribution of resources. It supports entities that simulate
networks used for communication among resources. During simulation, GridSim creates a number of
multi-threaded entities, each of which runs in parallel in its own thread. An entity’s behavior needs to
be simulated within its body() method, as dictated by SimJava.
A simulation environment needs to abstract all the entities and their time-dependent interactions in
the real system. It needs to support the creation of user-defined time-dependent response functions
for the interacting entities. The response function can be a function of the past, current, or both states
of entities. GridSim based simulations contain entities for the users, brokers, resources, information
service, statistics, and network based I/O, as shown in Figure 3. The design and implementation issues
of these GridSim entities are discussed below.
3.2.2.1. User. Each instance of the User entity represents a Grid user. Each user may differ from the
rest of users with respect to the following characteristics:
• types of job created, e.g. job execution time, number of parametric replications, etc.;
• scheduling optimization strategy, e.g. minimization of cost, time, or both;
• activity rate, e.g. how often it creates new job;
• time zone; and
• absolute deadline and budget; or
• D- and B-factors, deadline and budget relaxation parameters, measured in the range [0, 1]
express deadline and budget affordability of the user relative to the application processing
requirements and available resources.
3.2.2.2. Broker. Each user is connected to an instance of the Broker entity. Every job of a user is
first submitted to its broker and the broker then schedules the parametric tasks according to the user’s
scheduling policy. Before scheduling the tasks, the broker dynamically gets a list of available resources
from the global directory entity. Every broker tries to optimize the policy of its user and therefore,
brokers are expected to face extreme competition while gaining access to resources. The scheduling
algorithms used by the brokers must be highly adaptable to the market’s supply and demand situation.
3.2.2.3. Resource. Each instance of the Resource entity represents a Grid resource. Each resource
may differ from the rest of the resources with respect to the following characteristics:
• number of processors;
• cost of processing;
Copyright  2002 John Wiley & Sons, Ltd. Concurrency Computat.: Pract. Exper. 2002; 14:1175–1220
GridSim 1183
Jobs Appli
cation
Scheduler
User #i Broker #i Output
Input
Output
Input
Resource #j
Job In Queue
Job Out Queue Process
Queue
Output
Input
Resource
List
Information
Service
Internet
Writer #i
Report
Statistics
Recorder #i
Shutdown
Manager #i
Signal
Figure 3. A flow diagram in GridSim based simulations.
• speed of processing;
• internal process scheduling policy, e.g. time-shared or space-shared;
• local load factor; and
• time zone.
The resource speed and the job execution time can be defined in terms of the ratings of standard
benchmarks such as MIPS and SPEC. They can also be defined with respect to the standard machine.
Upon obtaining the resource contact details from the Grid information service, brokers can query
resources directly for their static and dynamic properties.
3.2.2.4. Grid information service. Providing resource registration services and keeping track of a list
of resources available in the Grid. The brokers can query this for resource contact, configuration, and
status information. ==
by isaackuku. email: isaackoko@gmail.com