Suzuki_DME - Token-Based Algorithms A unique token is...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Token-Based Algorithms A unique token is shared among all sites A site is allowed to enter a critical section (CS) if it possesses the token Token-based algorithms use sequence numbers instead of timestamps A site increments its sequence number counter every time it makes a request for the token Use sequence number to distinguish between old and current requests A correctness proof of token-based algorithms to ensure that DME is enforced is trivial because a site must hold the unique token before it can enter CS The issues of freedom from starvation and deadlock are prominent
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Suzuki-Kasami’s Broadcast Algorithm Raymond’s Tree Algorithm Suzuki-Kasami’s Broadcast Algorithm Overview To enter CS, a site broadcasts its REQUEST message to all other sites Upon receiving a REQUEST message, a site that has the token sends the token to the requesting site only if this site is not in CS. If it is in CS, it sends the token only after it has exited the CS A site can repeatedly enter CS as long as it holds the token and there are no pending requests from other sites
Background image of page 2
3 Major Design Issues No RELEASE/REPLY messages as in assertion- based protocols
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/11/2011 for the course CS 591 taught by Professor Annieliu during the Spring '11 term at SUNY Stony Brook.

Page1 / 9

Suzuki_DME - Token-Based Algorithms A unique token is...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online