Temporal notions of synchronization and consistency in Beehive
Aman Singla, Umakishore Ramachandran, Jessica K. Hodgins · 1997
An important attribute in the specification of many compute-intensive applications is "time".Simulation of interactive virtual environments is one such domain.There is a mismatch between the synchronization and consistency guarantees needed by such applications (which are temporal in nature) and the guarantees offered by current shared memory systems.Consequently, programming such applications using standard shared memory style synchronization and communication is cumbersome.Furthermore, such applications offer opportunities for relaxing both the synchronization and consistency requirements along the temporal dimension.In this work, we develop a temporal programming model that is more intuitive for the development of applications that need temporal correctness guarantees.This model embodies two mechanisms: "delta consistency" -a novel time-based correctness criterion to govern the shared memory access guarantees, and a companion "temporal synchronization" -a mechanism for thread synchronization along the time axis.These mechanisms are particularly appropriate for expressing the requirements in interactive application domains. in addition to the temporal programming model, we develop efficient explicit communication mechanisms that aggressively push the data out to "future" consumers to hide the read miss latency at the receiving end.We implement these mechanisms on a cluster of workstations in a software distributed shared memory architecture called "Beehive?Using a virtual environment application as the driver, we show the efficacy of the proposed mechanisms in meeting the real time requirements of such applications.