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, 2000. 

Proceedings. The Fourth International , Volume: 2 , 2000          Page(s): 738 -746 vol.2

Mike Tien

miketien@syslab.cse.yzu.edu.tw

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.)

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.)

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.)

Simulation Result and Performance(cont.)

Simulation Result and Performance(cont.)

Simulation Result and Performance(cont.)

Simulation Result and Performance(cont.)

4.Summary

Prediction by Domain-Top approach -- Top-10 -- 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.