Overview of P3

P3 is middleware for distributed computing with volatile PCs, in which participants provide and also use other's computers. This project is also an effort to develop such middleware on pure P2P facilities provided by JXTA.

Table of Contents

• PCs interacts with each other in a true P2P mode
• Parallel Processing Libraries and Emulator
• Job Management system
• Job Monitor

PCs interacts with each other in a true P2P mode

P3 utilizes JXTA (www.jxta.org), a widely accepted P2P communication library. P2P concepts which JXTA implements efficiently support P3:

• Discovery:
  PCs dynamically discover each other and jobs without a centralized server.
• Peer Group:
  PCs are grouped into job peer groups, where computers carry out code distribution, job control, and group communication for parallel computation (Fig. 1).
• Overlay:
  Enables end-to-end communication over NAT and firewall. Thanks to it, P3 supports parallel processing in the message passing model.

Fig. 1: Peer groups.

Parallel Processing Libraries and Emulator

Two parallel programming APIs to application writers are provided:

• Master-worker:
  Supports master-worker parallel processing. This library can confirm the correctness of calculation results collected from workers by voting. Application programmers do not have to be conscious of this confirmation and this function can be disabled when submitting an application.
• Message passing:
  In this model, each computer is identified by an integer, rank and a computer can send an object to another computer or all ones.

Fig. 2: Libraries and an emulator.

A parallel application using these libraries is usually hosted by P3 Job Management system, but the libraries are highly independent from it. It is possible to run the application with a simple wrapping program or other hosting facilities.

Job Management system

Job Management system conducts discovery of PCs and jobs, code distribution and execution control of submitted jobs. This subsystem consists of the following two programs:

• Controller (Fig. 3):
  • Resource users submit and control their jobs with this tool.
  • Controller has three types of user interfaces, as graphical user interface (GUI), character user interface (CUI) and Web browser.
• Host (Fig. 4):
  • A resource provider (PC contributor) runs this daemon program on their PCs.
  • A Host can run in a head(GUI)-less mode. In this case, it decides whether to host a found job or not according the digital signature on the job and a job acceptance policy supplied by the resource provider.
  • A Host can host multiple jobs simultaneously.

Fig. 3: Controller.

Fig. 4: Host.

Job Monitor

On a web browser, a resource user can monitor progress of calculation for submitted jobs.

Fig. 5: Job Monitor.

Fig. 6: Host Information part on Job Monitor screen.