Tracing.

Our simulator takes as input a trace of the pages a program touches, augmented with information about the compressibility and cost of compression of each touched page for a particular compression algorithm. To create such a trace and keep the trace size manageable, we used several steps and several tracing and filtering tools.

We traced each program using the portable tracing tool VMTrace [WKB]. We added a module to VMTrace that made it emit a complete copy of each page as it was referenced. We refer to such traces as page image traces.