The analysis of fork-join queueing systems has played an important role for the performance evaluation of distributed systems where parallel computations associated with the same job are carried out and the job is considered served only when all the parallel tasks it consists of are served and then joined. The fork&join nodes that we consider consist of K 2 parallel servers each of which is equipped with two FCFS queues, namely the service-queue and the join-queue. The latter store the serviced tasks waiting for being joined. This paper addresses the problem that under independent and exponentially distributed service time, the process describing the join-queue lengths becomes instable under heavy load. This is due to the variance of the service time distribution. We propose a simple mechanism that avoids this problem, show that we can analytically study a set of relevant performance indices and study by simulation its robustness.
|Titolo:||Dynamic control of the join-queue lengths in saturated fork-join queues.|
|Data di pubblicazione:||2016|
|Appare nelle tipologie:||4.1 Articolo in Atti di convegno|