Assessment of Response Time for New Multi Level Feedback Queue Scheduler

Response time is one of the characteristics of scheduler, happens to be a prominent attribute of any CPU scheduling algorithm. The proposed New Multi Level Feedback Queue [NMLFQ] Scheduler is compared with dynamic, real time, Dependent Activity Scheduling Algorithm (DASA) and Lockes Best Effort Scheduling Algorithm (LBESA). We abbreviated beneficial result of NMLFQ scheduler in comparison with dynamic best effort schedulers with respect to response time.Comment: 7 pages, 5 figure

On Intelligent Mitigation of Process Starvation In Multilevel Feedback Queue Scheduling

CPU time-share process schedulers for computer operating systems have existed since Corbato published his paper on the Compatible Time Sharing System in 1962 [8]. With this new type of scheduler came the need to effectively divide CPU time between N processes, where N could be 2 or more processes. Modern time-sharing process schedulers which have been developed in the decades since have been designed to favor shorter, interactive processes over long-running processes, especially when incoming demand for CPU time exceeds supply and process starvation is inevitable. These schedulers, including Linux CFS, FreeBSD Ule, and the Solaris Fair Share Scheduler, are all effective at favoring interactive processes under starvation conditions. Sometimes it’s not desirable that long-running processes be sacrificed altogether, but none of these schedulers have safeguards under starvation conditions. This thesis revisits and extends the research conducted in [13], in which it was demonstrated that starvation of long-running processes could be safely and effectively mitigated without adversely affecting the performance of shorter, interactive processes. The questions this thesis will answer are: Can MLFQ-NS, proposed in [13], be compared to other modern process schedulers? Can MLFQ-NS be improved? To answer the first question, a scheduler must be found which is similar enough to MFLQ for a direct comparison. This will require a survey of current schedulers. To answer the second question, the research conducted in [13] must be duplicated MLFQ-NS to ascertain the following: How much diverted time is actually used? Why does MLFQ-NS become ineffective past a certain system-load threshold, i.e. stop real- locating time to long-runnning processes? In this research, the original work was duplicated in simulations to validate previous re- sults, and determine why MLFQ-NS became ineffective after incoming CPU time demand exceeds a threshold. Research was conducted in order to determine if starvation mitigation in MLFQ-NS could be compared to other process schedulers used in production, with the conclusion that recent emphasis on priority scheduling and heurstic interactivity determination makes such a comparison impossible. Research then continued with simulations in which MLFQ-NS was given different run- time arguments than original simulations. Investigations into those results led to an algorithmic modification to MLFQ-NS called MLFQ-IM and analysis of simulations of MLFQ-IM. Conclu- sions about the effectiveness of MLFQ-IM will be explored. Finally, ideas for future research are offered

An Intelligent MLFQ Scheduling Algorithm (IMLFQ)

Scheduling algorithms are one of the most important algorithms in operating systems. These algorithms have been designed for optimized use of processes from processors. One of the best algorithms for scheduling processor is Multi Layer Feedback Queue (MLFQ), algorithm which is based on use of several queues with different quanta. The most serious problem of this method is the not being able to define the optimized number of queues and quantum of each queue for processing. These factors have a direct influence on the response time. In this article, a new algorithm has been presented for solving these problems and minimizing the response time. In this algorithm Recurrent Neural Network has been utilized for defining the optimized quantum of each queue, and number of queues. The simulations show that the IMLFQ algorithm, regarding response time and waiting time, act better than all the other algorithms which needless of having time for servicing processes schedule