The rendezvous is dead—long live the protected object
Dragan Maćoš, Frank Mueller · ACM SIGAda Ada Letters · 1998
This paper outlines the short-comings of rendezvous and the advantages of protected objects as a means of synchronization in Ada 95.A common Ada benchmark suite, ACES, gives the misleading impression that protected objects are cheaper per Be.This work shows that the main benefit of protected objects stems from the potential to reduce the number of context switches.Based on the latter observation, a general model to translate rendezvous into protected objects is developed.This model is further refined to replace entire server tasks that make calls to or accept rendezvous.A quantitative evaluation shows the benefits of protected objects for each approach and illustrates that the number of context switches can be reduced at least by 50% when tasks with rendezvous are replaced by protected objects resulting in significant execution time savings for applications requiring many synchronizations.