Performance Data

  The cache server has already been tested for two environments. In both environments the news server has been news.tuwien.ac.at. This news server holds approximately 35000 newsgroups.

Environment 1

News server

news.tuwien.ac.at

Machine

Cyrix 6x86 166+, 133MHz, 32MB memory (160MB virtual memory), 512KB second level cache, 10MBit network interface. The machine has been running the News Cache software only.

Client

DEC Alpha 21164, 366MHz, 1MB cache on the same local network.

Environment 2

News server

news.tuwien.ac.at

Machine

Intel 486, 66MHz, 24MB of memory (48MB virtual memory), 64KB second level cache. The machine is heavily loaded since it is also running the squid WWW cache. Squid usually uses 20MB of memory with 10MB usually being in core.

Client

Sun on the same local network.

Table 7.2 shows the performance measurements of two tests. The first column indicates the test. The second and third columns show the times required to satisfy the request by the News Cache and the time needed to satisfy the request from the news server (news.tuwien.ac.at).

The cache column gives the values for a cache miss (marked by an ``M'') and a cache hit (marked by an ``H''). The rows marked with ``$50\%$M'' shows the values for the same request, where every other request is a cache miss. Some of the entries in the news server column have been omitted since a cache miss cannot occur for requests to the news server.

 

Tabelle 7.2: Performance measurements

Test		2c|Cyrix	2c|I486
		Cache	Server	Cache	Server
Retrieving the active database	M
H	14s
2s	-
12s	228s
19s	-
20s
Selecting a newsgroup and retrieving 500 articles	M
$50\%$M
H	26s
20s
14s	-
-
10s	52s
44s
34s	-
-
21s
Selection of 150 newsgroups and retrieving the overview database of each	M
H	32s
10s	-
24s	292s
62s	-
38s