Improving WWW Performance Using Domain-Top approach to prefetching Seung Won Shin, Byeong Hag Seong and Daeyeon park Conference/Exhibition on High Performance Computing in the Asia-Pacific Region, Proceedings. The Fourth International, Volume: 2, 2000 Page(s): vol.2 Mike Tien

Outline 1.Introduction 2.Prefetching 3.Simulation Result and Performance 4.Summary 5.Conclusion

1.Introduction Top-10 --predicts the next requests by the prediction table consisting of the documents that accessed very frequently. --ad: It is simple and imposes very small burden on the proxy. --disa: It does only collect documents access frequently without analyzing the characteristics of requests.It does not cope with the rapid change of clients. Access-Tree --prediction table made by tree structure for measuring of correlation. --ad: It can predict the future request more accurately by probability. --disa: It has to manage complex data structure prediction table. It updated almost every time for each client request and determines the access probability of each resource.

Introduction(cont.) Domain-Top When most of clients find a domain that they want, they wait and watch the several documents in the domain. Top-domain--The domains that are requested frequently Top-Documents — the documents that are demanded most frequently in each Top-domain. Rank-list — It is a simple list, and it has an enough information to predict client future requests.

2.Prefetching Clients  ----  proxies  ----  servers There are two types of user-level processes. -- http-daemon — with support for persistent connections and pipeline requests. -- prediction-daemon — only manages and analyzes access log file in the proxy,not directly with client request.

Prefetching(cont.)

About Rank List -- How many domains are selected and how many documents are selected for each domain? -- a client moves about 20 domains in a day mainly.(by analyzed) -- prefetch 8 resources at once. ( the number of documents for prefetching increases, hit ratio of the prefetching grows, but its growing rate is so small and saturated in a moment )

Prefetching(cont.)

When to make the Rank List?(AM 7:00)

Prefetching(cont.) Persistent connection and Pipelining Request through GETLIST method -- We use HTTP 1.1 persistent connection for retrieving the multiple resources.This makes it possible to take several resources in one connection. -- GETLIST allows a client to request a set documents or images from a server.( a series of GETs)

3.Simulation Result and Performance Average size of all files that were prefetched is 40 KB. No more than 8 resources can be prefetched during one prefetching time period.

Simulation Result and Performance(cont.)

4.Summary Prediction by Domain-Top approach -- Top Access-Tree -- Domain-Top Lightweight prediction Table: Rank List Small variation of hit ratio Small change of the proxy Small burden on the network -- persistent connection -- GETLIST

5.Conclusion and Future Work Domain-Top approach can be implement very easily. And it can analyze a user ’ s Web surfing experience with small burden on the proxy. We will suggest the new approach to predict in client-side, and combine this item with our Domain-Top approach.