This section demonstrates the base performance of plugins using two micro-benchmarks, two macro-benchmarks, and finally, an evaluation of the utility and practicality of plugins with a realistic image-transcoding plugin. The latter color-downsamples images using an application-specific integer-only method as per some client's needs.
Experimental results reported in this section are obtained on an 866 MHz Pentium III processor, with 16 KB L1 I&D caches, 256 KB unified L2 cache, 512 MB of PC133 RAM, and a 20 GB Western Digital WD205AA hard drive used in UDMA66 mode. The operating system is Fedora Core 1 running Linux kernel version 2.4.19 augmented by our kernel plugin facility.
Timing is performed using the Pentium processor's internal time-stamp
counter (TSC), except for the httperf [17]
macro-benchmark which uses much coarser granularity system timers. The
TSC is a 64-bit register zeroed at power-up and incremented by exactly
1 with each clock tick of the CPU core. Its 2 
error is
insignificant in comparison to statistical variations in experimental
data.