Web Caching

Sample Benchmark Results

This section contains results from a Web Polygraph benchmark of a Squid cache. The data shown here is not an official Polygraph result, but it uses the same PolyMix-3 workload that we used for the third industry Cache-Off.

For this test, Squid is running on a Compaq Proliant system with an Intel Pentium III/450 processor, 1GB of RAM, six 9GB SCSI disks, and an Intel fast Ethernet interface. The operating system is FreeBSD-4.1 with a kernel specifically tuned for Squid. The Squid version is 2.4.DEVEL4.

PolyMix-3 has three input parameters: cache size, peak throughput, and fill rate. For this test, the cache size is 41G B, the peak throughput is 130 requests per second, and the fill rate is 115 requests per second. Another characteristic of the workload is its different phases. PolyMix-3 has three interesting phases: fill, top1, and top2. There are actually transitional phases in between, but we won’t discuss them. The fill rate is the request rate during the fill phase, which can be different from the peak throughput for the top phases. During the fill phase, the hit ratio is only 5%, whereas it is about 57% during the top phases. During the fill phase, the cache is mostly writing objects to disk, with relatively few reads. Thus, a cache may be able to support a higher throughput during the top2 phase, when it is reading more and writing less than it was during the fill phase.

These results were created by running Polygraph’s ReportGen scripts. Rather than ...