• Title/Summary/Keyword: thrashing

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Reducing the frequency of processor thrashing using guarantee/reservation in process migration (작업 이주시 보장/예약 기법을 이용한 프로세서 쓰레싱 빈도 감소)

  • Lee, Jun-Yeon;Im, Jae-Hyeon
    • The KIPS Transactions:PartA
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    • v.8A no.2
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    • pp.133-146
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    • 2001
  • In a dynamic load distribution policies, each node gathers the current system sates information before making a decision on load balancing. Load balancing policies based on this strategy can suffer from processor thrashing. In this paper, we propose a new algorithm which attempts to decrease the frequency of the processor thrashing, the algorithm is based on the integration of three components. The first, the algorithm of which determine the size of jobs be transferred. The second, negotiation protocol with obtains a mutual agreement between a sender and a receiver on the transferring job size. And the third, a symmetrically-initiated location policy. The algorithm proposed in this paper used Siman IV as simulation tool to prove the improvement of performance. I analyzed the result of simulation, and compared with related works. The mean response time shows that there are no difference with existing policy, but appear a outstanding improvement in high load. The thrashing coefficient that shows the average response time, CPU overhead and the thrashing ratio at both the receiving and sending node has been used in the analysis. A significant improvement in the average response time and the CPU overhead ratio was detected using our algorithm when an overhead occurred in the system over other algorithm. The thrashing coefficient differed in the sending node and the receiving node of the system. Using our algorithm, the thrashing coefficient at the sending node showed more improvement when there was an overhead in the system, proving to be more useful. Therefore, it can be concluded that the thrashing ratio can be reduce by properly setting the maximum and minimum value of the system’s threshold queue.

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Reuse Information based Thrashing Resistant Cache Management Scheme

  • Sim, Gyu Yeon;Kim, Cheol Hong
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.3
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    • pp.9-16
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    • 2017
  • In recent computing systems, LRU replacement policy has been widely used because it can be simply implemented and applicable to most programs. However, if the working set size of the program is bigger than the actual cache size, LRU replacement policy may occur thrashing problem. Thrashing problem means that cache blocks are consistently replaced without re-referencing in the cache. This paper proposes a new cache management scheme to solve the thrashing problem in the second-level cache. The proposed scheme measures per set reuse frequency using EAF structure to find thrashing sets. When the cache miss occurs, it tests whether the address of the missed block is stored or not. If the address of the missed block is stored, it means that the recently evicted block is re-requested, so the reuse frequency is predicted high. In this case, the corresponding counter of the set is increased. When the counter value is bigger than the threshold value, we assume that the corresponding set shows high reuse frequency. The proposed scheme assigns the set with high reuse frequency to the additional small size cache to keep the blocks in the cache for a long time. Our experimental results show that the proposed scheme improves the IPC by 3.81% on average.

Analysis and Management Policies for Memory Thrashing of Swap-Enabled Smartphones (스왑 지원 스마트폰의 메모리 쓰레싱 분석 및 관리 방안)

  • Hyokyung Bahn;Jisun Kim
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.2
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    • pp.61-66
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    • 2023
  • As the use of smartphones expands to various areas and the level of multitasking increases, the support of swap is becoming increasingly important. However, swap support in smartphones is known to cause excessive storage traffic, resulting in memory thrashing. In this paper, we analyze how the thrashing of swaps that occurred in early smartphones has changed with the advancement of smartphone hardware. As a result of this analysis, we show that the swap thrashing problem can be resolved to some extent when the memory size increases. However, we also show that thrashing still occurs when the number of running apps continues to increase. Based on further analysis, we observe that this thrashing is caused by some hot data and suggest a way to solve this through an NVM-based architecture. Specifically, we show that a small size NVM with judicious management can resolve the performance degradation caused by smartphone swap.

A Study on Adbanced Load Balancing for Hypercube distributed System (하이퍼큐브 분산 시스템에서 향상된 부하분산에 관한 연구)

  • Yu, Jae-Wook;Park, In-Kap;Kim, Joong-Min
    • Journal of IKEEE
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    • v.6 no.1 s.10
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    • pp.87-93
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    • 2002
  • In this paper, an advanced load balancing algorithm in nth order Hypercube distributed system has been proposed. The new algorithm uses centralized load-balancing to avoid blocking phenomenon and processor thrashing, and shows the results which makes loads to approach average value of loads. The new algorithm is compared with several other algorithm and it shows a merit in cost function value.

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A Study on the 'Closed ㄱㄴ Type' of Traditional Folk Housing in Goyang, Gyonggi-do, Focused to Dweller's Life (거주자 생활중심으로 본 경기 고양 전통민가 연구 - 폐쇄형 ㄱㄴ자집을 중심으로 -)

  • Lee, Hee-Bong
    • Journal of architectural history
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    • v.14 no.3 s.43
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    • pp.53-76
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    • 2005
  • Through a field study of the folk houses, 'Closed ㄱㄴ Type' in Goyang-si, Gyonggj-do, focused on the dweller's life by the method of ethnographic interview, observation, and physical survey. L and opposite L type of inner and outer buildings form a closed inner court, and innermost backyard for woman is enclosed by fence. Form and space of the house contains dweller's traditional life. Outer space of a front gate becomes semiprivate space, for thrashing and piling up harvest and raising vegetables and pigs. Confucius principle does not fully dominate dweller's life of ancestral rite at Daecheong floor, and separation of man's and woman's quarter. Superstitious worship activities took place for lord of site and house. In everyday life, Anbang, inner main room, is assigned for parent's quarter instead of woman's quarter, and Geornbang, next room, was for son's family. Anbang has symbolic meaning for a place of deathbed. House contains agricultural activities, crop harvesting, thrashing, putting into storage, hulling rice, and keeping grain near kitchen. At present, rooms are needed more; sheds are made into rooms, rooms are enlarged toward outside, half outside space like Daechong floor becomes interior space by sash screen. And modern facilities of kitchen and bathroom are equipped for convenience. At the end, meaning and generative principle of those forms are discovered.

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Investigation on the Use of Paraquat and Diquat as a Desiccant for Sesame Harvest-Aid (참깨 수확을(收穫) 위한 건조제(乾燥劑)로서 Paraquat와 Diaquat의 이용(利用)에 관(關)한 연구(硏究))

  • Han, S.S.;Park, K.H.;Yoo, C.H.;Lee, Y.K.
    • Korean Journal of Weed Science
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    • v.13 no.1
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    • pp.7-13
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    • 1993
  • Experiments were carried out to investigate the utilization of paraquat and diquat as desiccants for harvest-aid of sesame. When paraquat and diquat were sprayed at 3days or 3hours before cutting of sesame plants, moisture content in treated plots was evenly rapidly decreased and sesame yeild was not significantly different as compared with that in untreated plot. Percentage of germination of sesame seed in treated plots was similar to that in untreated check. Residual amount in sesame seed was not detectable when these chemicals were treated with 250ppm at 3days before cutting of sesame plant. Percentage of thrashing was high in sesame plants treated with paraquat and diauat with the lapse of time after cutting. Required labor in thrashing of sesame was reduced when applied with these chemicals. Harvest efficiency of sesame after spray of paraquat and diquat was good by comparison with the traditional practice.

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A Study on Adbanced Load Balancing for Multiprocessor System (다중처리 시스템에서 향상된 부하분산에 관한 연구)

  • 김중민;유재욱;박인갑
    • Proceedings of the IEEK Conference
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    • 2002.06a
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    • pp.243-246
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    • 2002
  • In this paper, an advanced load balancing algorithm in nth order Hypercube distributed system has been proposed. The new algorithm uses centralized load-balancing to avoid blocking phenomenon and processor thrashing, and shows the results which makes loads to approach average value of loads. The new algorithm os compared with several other algorithm and it shows a merit in cost function value.

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Reducing the frequency of the processor thrashing using guarantee/reservation (보장/예약 기법을 이용한 프로세서 쓰레싱 감소 방안)

  • Lee, Jun-Yeon;Lim, Jae-Hyun
    • Proceedings of the Korea Information Processing Society Conference
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    • 2000.04a
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    • pp.194-199
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    • 2000
  • 동적 부하 분산 정책은 시스템의 상태를 고려하여 부하 균등화를 결정한다. 이를 위하여 분산형 정책에서는 각 노드가 부하 균등화를 결정하기 전에 적절한 부하 전송 대상을 찾기 위하여 현재의 시스템 상태 정보를 수집한다. 그러나 이 과정에서 프로세서 쓰레싱이 발생하게 된다. 본 논문에서는 프로세서 쓰레싱의 발생 빈도를 감소시키기 위한 새로운 알고리즘을 제안하였다. 그리고 모의실험을 통하여 제안된 알고리즘의 성능 개선을 증명하였다.

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Block Associativity Limit Scheme for Efficient Flash Translation Layer (효율적인 플래시 변환 계층을 위한 블록 연관성 제한 기법)

  • Ok, Dong-Seok;Lee, Tae-Hoon;Chung, Ki-Dong
    • Journal of KIISE:Computing Practices and Letters
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    • v.16 no.6
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    • pp.673-677
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    • 2010
  • Recently, NAND flash memory has been widely used in embedded systems, personal computers, and server systems because of its attractive features, such as non-volatility, fast access speed, shock resistance, and low power consumption. Due to its hardware characteristics, specifically its 'erase-before-write' feature, Flash Translation Layer is required for using flash memory like hard disk drive. Many FTL schemes have been proposed, but conventional FTL schemes have problems such as block thrashing and block associativity problem. The KAST scheme tried to solve these problems by limiting the number of associations between data block and log block to K. But it has also block thrashing problem in random access I/O pattern. In this paper, we proposed a new FTL scheme, UDA-LBAST. Like KAST, the proposed scheme also limits the log block association, but does not limit data block association. So we could minimize the cost of merge operations, and reduce merge costs by using a new block reclaim scheme, log block garbage collection.

Distributed Indexing Methods for Moving Objects based on Spark Stream

  • Lee, Yunsou;Song, Seokil
    • International Journal of Contents
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    • v.11 no.1
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    • pp.69-72
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    • 2015
  • Generally, existing parallel main-memory spatial index structures to avoid the trade-off between query freshness and CPU cost uses light-weight locking techniques. However, still, the lock based methods have some limits such as thrashing which is a well-known problem in lock based methods. In this paper, we propose a distributed index structure for moving objects exploiting the parallelism in multiple machines. The proposed index is a lock free multi-version concurrency technique based on the D-Stream model of Spark Stream. The proposed method exploits the multiversion nature of D-Stream of Spark Streaming.