在本論文中，我在Linux系統中提出了一個新的低負擔傳輸協議。而提出此一新的傳輸協議是因為，在原來的Linux傳輸或是接收中，需要多於一次的記憶體複製，而這些記憶體複製是不需要的。所以在本論文中，我將實做出只有一次的記憶體複製的傳輸協定，也稱做為zero copy。

In this thesis, a low overhead transport protocol for Linux networking is proposed. This proposed
protocol is motivated by the observation that the transport protocol for Linux requires more than a single memory copy for both the receiving and transmission of a packet, which is essentially redundant. In this thesis, we show that all but one of the memory copies can be eliminated, thus reducing the number of memory copies to one and only one, which is in general referred to as zero copy.

List of Figures iii
List of Listings v
List of Tables vii
謝誌viii
Chapter 1 Introduction 1
1.1 Network in Linux System . 1
1.2 Motivations . . 2
1.3 Organization of the Thesis 4
Chapter 2 Sending and Receiving Packet 5
2.1 Sending a Packet . . 5
2.2 Receiving a Packet . 12
Chapter 3 Relationships Between the Structure Socket Sock and Socket Buffers 15
3.1 Structure Socket 15
3.2 Structure Sock . 17
3.3 Structure Socket and Structure Sock . 18
3.4 Socket Buffer . 19
3.5 Manipulate Socket Buffer 22
Chapter 4 Memory Address in the Linux 26
4.1 Address Translation . 26
4.1.1 Physical Address and Page Frame Number Translation . . 27
4.1.2 Virtual Address and Page Frame Number Translation 29
4.1.3 PFN and Structure Page 31
4.1.4 Address Translation Conclusion . . 32
4.2 Memory Mapping . . 33
4.2.1 Process and Virtual Memory Area . 34
Chapter 5 The Proposed Protocol 35
5.1 Zero Copy 35
5.2 Device driver and Protocol 36
5.3 Register a Socket . . 37
5.4 Functions 40
5.4.1 Creating Function 40
5.4.2 Binding Functions 42
5.4.3 Sending and Receiving Functions . 42
5.5 Write and Read to/form Shared Memory . . 45
5.5.1 Initial the Shared Memory . . 46
5.5.2 Update the Data . . 48
5.5.3 Getting the Address 51
5.6 Synchronization Problem . 51
5.7 Exit 51
5.8 New APIs 53
Chapter 6 Performance Evaluation 60
6.1 Test Programs . 60
6.2 Experimental Results 84
Chapter 7 Conclusion and Future Works 88
7.1 Conclusion . . 88
7.2 Future Works . 88

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