由於目前電腦硬體發展的趨勢朝向多核心的機器架構，特別是在需要許多運算資源的應用上，多數的電腦應用也開始使用並行運算以期能提升整體運算的效能，例如典型的3D即時運算遊戲。然而在並行運算的環境中，如何有效地對共享資源做衝突偵測與衝突管理成為影響整體效能的重要關鍵之一。為了要保護共享資源，廣為人知的方法便是使用Locks，但這個方法卻會導致一些問題的產生，例如死結，缺乏並行性等。因此研究者使用一種新的方法稱作Transactional Memory(TM)來取代傳統的locks。雖然TM提供了atomicity、consistency、isolation，也就是所謂的serializability等安全特性，然而在許多應用的效能研究上，包括3D遊戲，卻發現TM的效能相較於locks是比較差的。而這也是為何現在我們仍舊使用locks來處理衝突問題的原因。
　　在這篇研究中，為了要同時獲得較好的效能又能確保共享資源的安全性與正確性，我們設計了兩種方法：Barrier Transactional Memory與Aggregate Physics Update。Barrier TM會利用TM的特性來做衝突針測與管理，而後Aggregate Physics Update會使用多執行緒機制來將所有運算結果更新。雖然利用TM做衝突偵測與管理必須付出一些效能的代價，但Barrier TM能夠偵測衝突使得進入Physics Steps的Thread能夠並行地處理，從而提升整體的效能。為了測試與驗證我們的方法，我們建立了一個模擬並且比較我們的方法與locks傳統方式的差異，結果顯示我們的方法有機會能夠提升整體遊戲伺服器系統的效能，同時也能夠讓並行遊戲運算伺服器環境中的共享資源處理上更為安全。

Because of the trend toward multi-core machines, a number of practical computer applications have started to support parallel computing in order to maximize performance efficiency, especially in applications which need a lot of computing resources, such as 3D games; nevertheless with a parallel computing supported applications executed in a multi-core environment, how to do the concurrency control on shared resources could be an important factor related to the performance and accuracy. To protect the shared resources in a parallel computing environment, well- known mechanisms such as locks, semaphores, or monitors have been widely used in many applications, but they may lead to problems such like deadlock, lacking composability, etc. Thus, researchers have developed a new mechanism called Transactional Memory (TM). TM provides safe characteristics that include atomicity, consistency, isolation, which means serializability for using shared resources and also ease the programming difficulty for programmers. However, in applications like 3D games, the performance of TM in most research studies has been relatively poorer than traditional methods, and that is why we still use the locks to handle the concurrency control nowadays.
In this thesis, in order to achieve better performance with ensuring correctness of concurrent accesses of shared resources in a multi-player game server system, we have designed two mechanisms named Barrier Transactional Memory and Aggregate Physics Update. The Barrier TM utilizes the good characteristics of transactional memory to detect and release signals without conflict, and Aggregate Physics Update can update all calculation results using parallel multi-threading, aiming to speed up overall performance of a parallel multiple-player game server system. To test and verify our mechanism, we conduct simulation experiments that compare Barrier TM and Aggregate Physics Update to traditional locking mechanism and single thread update to see if we can gain more efficiency for the overall system. Our results show that it is possible to improve the performance of a game server system, especially in the area of physics calculations and updating, and also that it is possible to provide a safe shared resource that can be applied in a parallel game server computing environment.

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