【摘要】：現(xiàn)代計算機系統(tǒng),無論是操作系統(tǒng)還是編程語言、虛擬機等,都采用自動內存管理技術。自動內存管理,即垃圾收集,是指自動回收內存中無用對象的機制。除了采用更高性能的硬件,充分優(yōu)化的軟件設計來提高用戶程序的性能,改進垃圾收集算法也是提高性能的重要手段。 傳統(tǒng)的半區(qū)復制收集器采用保守的空間預留策略,缺乏自適應性。本文圍繞半區(qū)復制收集器,展開了如下工作： 1.詳細地研究了各種垃圾收集策略,分析了各種收集算法的特性,并列舉了每種收集策略的不同實現(xiàn)形式的垃圾收集器,探討了垃圾收集器的發(fā)展規(guī)律。 2.系統(tǒng)地分析了Cheney節(jié)點復制算法和Lisp2標記縮并算法的原理、內存空間設計和優(yōu)缺點。針對采用對稱半區(qū)的傳統(tǒng)節(jié)點復制收集器無法充分利用內存的缺陷,結合弱分代假設和程序運行的可預測性,提出了動態(tài)調整兩個半區(qū)比例的非對稱雙空間復制算法。 3.給出了非對稱雙空間復制收集器的內存空間設計,修改了節(jié)點復制算法、標記縮并算法,通過全新設計的空間調整模塊將兩個算法結合在一起。隨后實現(xiàn)了非對稱雙空間收集器,設計了詳細的實驗方案對其進行了充分的測試,證明了它能夠有效提高垃圾收集的效率。 4.針對基于節(jié)點復制算法的收集器在存活量接近堆的一半出現(xiàn)嚴重性能衰退的缺陷,結合標記縮并收集器此時的優(yōu)良性能,設計了模式切換模塊,在非對稱雙空間復制收集器和標記縮并收集器的基礎上實現(xiàn)了自動切換模式的非對稱雙空間混合收集器。同樣地對它進行了各項測試,驗證了其在高存活率情況下的性能優(yōu)勢。
[Abstract]:Modern computer systems, whether operating system or programming language, virtual machine, etc., adopt automatic memory management technology. Automatic memory management, or garbage collection, refers to the mechanism of automatically collecting useless objects in memory. In addition to using higher-performance hardware, fully optimized software design to improve the performance of user programs, improving garbage collection algorithm is also an important means to improve performance. The traditional half-zone replication collector adopts conservative space reservation strategy and lacks self-adaptability. In this paper, the following work has been done around the half-zone replication collector: 1. In this paper, various garbage collection strategies are studied in detail, the characteristics of various collection algorithms are analyzed, and the garbage collectors with different implementation forms of each collection strategy are enumerated, and the development rules of garbage collectors are discussed. 2. The principle, memory space design, advantages and disadvantages of Cheney node replication algorithm and Lisp2 tag merging algorithm are analyzed systematically. In view of the disadvantage that the traditional node replication collector with symmetrical half-zone can not make full use of memory, combined with weak generation hypothesis and the predictability of program operation, an asymmetric double-space replication algorithm is proposed to dynamically adjust the proportion of two half-regions. 3. In this paper, the memory space design of asymmetric dual space replication collector is given, and the node replication algorithm and label join algorithm are modified. The two algorithms are combined by a new space adjustment module. Then an asymmetric dual-space collector is implemented and a detailed experimental scheme is designed to test it. It is proved that it can effectively improve the efficiency of garbage collection. 4. Aiming at the defect that the collector based on node replication algorithm has serious performance degradation in half of the existing capacity near the heap, a mode switching module is designed based on the excellent performance of the tag contraction collector at this time. Based on asymmetric dual-space replication collector and tag contraction collector, an asymmetric dual-space hybrid collector with automatic switching mode is implemented. In the same way, it is tested to verify its performance advantage in the case of high survival rate.
【學位授予單位】：華東理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TP333;TP301.6

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本文編號：2452059