On-line scheduling algorithms for reducing the largest weighted error incurred by imprecise tasks

2002 ◽  
Author(s):  
Chunhee Lee ◽  
Won Ryu ◽  
Kihyun Song ◽  
Kyunghee Choi ◽  
Gihyun Jung ◽  
...  
Keyword(s):  
Scheduling Algorithms ◽  
On Line ◽  
Weighted Error

scholarly journals A Pruning-Based Disk Scheduling Algorithm for Heterogeneous I/O Workloads

2014 ◽  
Vol 2014 ◽  
pp. 1-17
Author(s):  
Taeseok Kim ◽  
Hyokyung Bahn ◽  
Youjip Won
Keyword(s):  
Response Time ◽  
Scheduling Algorithm ◽  
Scheduling Algorithms ◽  
Disk Scheduling ◽  
Best Effort ◽  
Qos Guarantees ◽  
Time Minimization ◽  
On Line ◽  
Manageable Level ◽  
Deadline Constraints

In heterogeneous I/O workload environments, disk scheduling algorithms should support different QoS (Quality-of-Service) for each I/O request. For example, the algorithm should meet the deadlines of real-time requests and at the same time provide reasonable response time for best-effort requests. This paper presents a novel disk scheduling algorithm called G-SCAN (Grouping-SCAN) for handling heterogeneous I/O workloads. To find a schedule that satisfies the deadline constraints and seek time minimization simultaneously, G-SCAN maintains a series of candidate schedules and expands the schedules whenever a new request arrives. Maintaining these candidate schedules requires excessive spatial and temporal overhead, but G-SCAN reduces the overhead to a manageable level via pruning the state space using two heuristics. One is grouping that clusters adjacent best-effort requests into a single scheduling unit and the other is the branch-and-bound strategy that cuts off inefficient or impractical schedules. Experiments with various synthetic and real-world I/O workloads show that G-SCAN outperforms existing disk scheduling algorithms significantly in terms of the average response time, throughput, and QoS-guarantees for heterogeneous I/O workloads. We also show that the overhead of G-SCAN is reasonable for on-line execution.

A lower bound for randomized on-line scheduling algorithms

1994 ◽  
Vol 51 (5) ◽  
pp. 219-222 ◽  
Author(s):  
Bo Chen ◽  
André van Vliet ◽  
Gerhard J. Woeginger
Keyword(s):  
Lower Bound ◽  
Scheduling Algorithms ◽  
On Line
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