Laplace: Merging Background


Merging the raw reference trace and the kernel event trace is superficially a simple task: Each record from both traces use the processor's cycle counter to generate timestamps, and so a simple interleaving of the records is trivial. However, for many simulation purposes, it is desirable to correlate kernel events with references in order to produce a final, merged result that is more than just the simple interleaving. Specifically, it is desirable at the merging step to reconstruct the memory mappings at each moment of execution. In that way, the interleaved trace can contain information about the use of shared pages and filesystem cache pages.

We describe here the basics of post-processing merge phase as implemented in the Laplace-merge utility. A more detailed description is available in a paper that has been submitted for publication and can be obtained by request.

This page is not yet complete. The code for Laplace-merge is well documented, and other sections of the documentation describe different merge formats.


Scott F. Kaplan
Last modified: Sat Nov 30 09:32:18 EST 2002