• Journal of Internet Computing and Services
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• v.5 no.6
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• pp.11-20
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• 2004

Proportional Fair (PF) share policy has been adopted as a downlink scheduling scheme in CDMA2000 l×EV-DO standard. Although It offers optimal performance in aggregate throughput conditioned on equal time share among users, it cannot provide a bandwidth guarantee and a strict delay bound. which is essential requirements of real-time (RT) applications. In this study, we propose a new scheduling policy that provides quality-of-service (QoS) guarantees to a variety of traffic types demanding diverse service requirements. In our policy data traffic is categorized Into three classes, depending on sensitivity of Its performance to delay or throughput. And the primary components of our policy, namely, Proportional Fair (PF), Weighted Fair Queuing (WFQ), and delay-based prioritized scheme are intelligently combined to satisfy QoS requirements of each traffic type. In our policy all the traffic categories run on the PF policy as a basis. However the level of emphasis on each of those ingredient policies is changed in an adaptive manner by taking into account the channel conditions and QoS requirements. Such flexibility of our proposed policy leads to offering QoS guarantees effectively and. at the same time, maximizing the throughput. Simulations are used to verify the performance of the proposed scheduling policy. Experimental results show that our proposal can provide guaranteed throughput and maximum delay bound more efficiently compared to other policies.

• Journal of KIISE
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• v.44 no.5
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• pp.469-475
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• 2017

The emerging NVMe-based multi-queue SSDs provides a high bandwidth by parallel I/O, i.e., each core performs I/O through its dedicated queue in parallel with other cores. To provide a bandwidth share for each application with I/O, a fair-share scheduler that provides a bandwidth share to each core is required. In this study, we proposed a multi-core scalable fair-queuing algorithm for multi-queue SSDs. The algorithm adopts randomization to minimize the inter-core synchronization overheads and provides a weight-proportional bandwidth share to each core. The results of our experiments indicated that the proposed algorithm gives accurate bandwidth partitioning and outperforms the existing FlashFQ scheduler, regardless of the number of cores for a Linux kernel with block-mq.

• Journal of Korea Multimedia Society
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• v.4 no.5
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• pp.371-376
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• 2001

Since continuous media such as video and audio data are displayed within a certain time constraint, their computation and manipulation should be handled under limited condition. Traditional real-time scheduling algorithms cold be directly applicable, because they are not suitable for multimedia scheduling applications which support many clients at the same time. Rate Regulating Proportional Share Scheduling Algorithm based on the stride scheduler is a scheduling algorithm considered the time constraint of the continuous media. The stride schedulers, which are designed to general tasks, guarantee the fairness of resource allocation and predictability. The key concept of RRPSSA is a rate regulator which prevents tasks from receiving more resource than its share in a given period. But this algorithm loses fairness which is a strong point of the stride schedulers, and does not show graceful degradation of performance under overloaded situation. This paper proposes a new modified algorithm, namely Modified Proportional Share Scheduling Algorithm considering the characteristics of multimedia data such as its continuity and time dependency. Proposed scheduling algorithm shows graceful degradation of performance in overloaded situation and it reduces the scheduling violations up to 70% by maintaining the fair resource allocation. The number of context switching is 8% less than RRPSSA and the overall performance is increased.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.238-244
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• 2007

Guaranteed Frame Rate(GFR), recently approved by the ATM Forum, expects to become an important service category to efficiently support TCP/IP traffic in ATM networks. The GFR service not only guarantees a minimum service rate at the frame level, but also supports a fair share of available bandwidth. We proposed new scheduling scheme for the GFR service. Proposed scheme provides priority to VCs and high priority to a VC which have more untagged cells in buffer. High priority VCs have much more serviced than low priority. Proposed scheme can provide MCR(minimum cell rate) guarantee and fair sharing to GFR VCs. Computer simulation results show that proposed scheduling scheme provide a much better performance in TCP goodput and fairness than previous scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2A
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• pp.98-106
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• 2005

We propose a new wireless fair queueing algorithm, WFQ-R (Wireless Fair Queueing with Retransmission), which is well matched with the LLR (Link Level Retransmission) algorithm and does not require channel prediction. In the WFQ-R algorithm, the share consumed by retransmission is regarded as a debt of the retransmitted flow to the other flows. Thus, the WFQ-R algorithm achieves wireless fairness with the LLR algorithm by penalizing flows that use wireless resources without permission under the MAC layer. Through simulations, we showed that our WFQ-R algorithm maintains fairness adaptively and maximizes system throughput. Furthermore, our WFQ-R algorithm is able to achieve flow separation and compensation.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.12-18
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• 2021

A proportional share scheduler allocates CPU time to tasks and determines which task will be dispatched according to their priorities. In this paper, we investigate the correlation between the characteristics of applications and task priorities in the Linux Completely Fair Scheduler(CFS), which is one of the representative proportional share schedulers. We also propose a method of controlling the granularity of priority assignments according to the characteristics of applications. We implemented the proposed technique in a Linux system and confirmed the meaningful experimental results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.9
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• pp.12-19
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• 2002

Guaranteed Frame Rate(GFR) service is intended to efficiently support TCP/IP traffic in ATM networks. The GFR service not only guarantees a minimum service rate at the frame level, but also supports a fair share of available bandwidth. The original GFR proposal outlined two switch implementation scheme : FIFO Queuing and perVC-Queuing. In general, it has been shown that FIFO Queuing is not sufficient to provide rate guarantees and perVC-Queuing with scheduling is needed. In perVC-Queuing implementation, scheduling algorithm plays key rule to provide rate guarantees and to improve fairness. We proposed a new scheduling algorithm for the GFR service. Proposed algorithm can provide minimum service rate guarantee and fair sharing to GFR VCs. Computer simulation results show that proposed scheduling scheme provide a much better performance in TCP Goodput and fairness than previous scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1665-1674
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• 2000

This paper treats the interworking of LAN-based networks like TCP over the ATM protocol stack in an ATM multicast session. Multicast connection will cause CIP since multicast group members form a connection tree by some tree methods and share the connected tree. The paper solve the CIP problem through a block-by-block transmission using ABT/IT method. ABT/IT RM cell is modified and block scheduling algorithm considering the traffic types is applied to each ATM switch using the enhanced RM cell. Block scheduling algorithm will avoid the indiscriminate discard of UBR traffic when congestion occurs and it can provide an efficient and fair service. The paper builds a block scheduler system and suggests the block scheduling algorithm for a multicast session in an ATM switch. UBR traffics arriving at the switch trough each VC is classified by the traffic type and stored at class buffer and thereafter indisciminately transmitted. When block scheduling algorithm is applied it will improve the UBR traffic performance such as end-to-end delay cell block loss ration etc. This paper evaluated the performance of block scheduling algorithm through the simulation using the C language and data structure.

• Journal of the Korea Society of Computer and Information
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• v.16 no.11
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• pp.45-56
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• 2011

WBAN is short range wireless communication technology which is consists of several small devices close to, attached to or implanted into the human body. WBAN is classified into between medical and non-medical by applications based on technology and medical data with periodic characteristics is used the GTS method for transmitting data to guarantee the QoS. In this paper we proposed algorithm that resolve lack of GTSs while data transmit GTS method in superframe structure of WBAN. Coordinator dynamically allocates GTSs according to the data rate of devices and make devices share GTSs when lack of GTSs. We compared delay bounds, throughput for performance evaluation of the proposed algorithm. In other words, we proposed algorithm adaptive WFQ scheduling that GTS allocation support differential data rate in environments of WBAN. The experiment results show the throughput increased and the maximum delay decreased compared with Round Robin scheduling.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1099-1107
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• 2005

The Guaranteed Frame Rate(GFR) service has been designed to accomodate non-real-time applications, such as TCP/IP based traffic in ATM networks. The GFR service not only guarantees a minimum throughput at the frame level, but also supports a fair share of available resources. In this paper, we propose a cell scheduling scheme which can improve the fairness and the goodput through the traffic control in GFR service. For the evaluation of the proposed scheme, we compare the proposed scheme with the existing scheme in the fairness and the goodput. Simulation results show that proposed scheme can improve the fairness and goodput comparing with the existing buffer management scheme.