Laplace: Downloads

The Laplace code is thoroughly commented, and each piece comes with its own doxygen-generated code documentation. For a richer description of Laplace at a high level as well as various Laplace utilities, go to the documentation page.

A pre-configured Laplace machine

The easiest way to get started with Laplace to to download this tarball. It includes a pre-compiled Laplace-on-Bochs machine simulator, ready for use on Linux/x86 machines; a disk image that contains a full Slackware installation and a Laplace-modified kernel, and configuration files to start running Laplace-on-Bochs immediately. Once you've downloaded this tarball, see the documentation for getting started.

• Laplace 0.8 whole machine: This tarball extracts to a single directory that contains a complete Laplace machine that is ready to run. Specifically, it contains a unmodified Bochs executable, a Laplace-modified Bochs executable, the necessary configuration and support files needed by Bochs at runtime, and a disk image file that contains a pre-installed Slackware installation with a Laplace-modified kernel in place.

The simulated machine

• Bochs 1.4 tarball: The actual processor/machine simulator that forms the basis of Laplace.
• Laplace 0.8 Bochs patch: The patch to the Bochs code to make it record references and kernel events. Note that this patch includes the configuration for a bochs machine with the desired characteristics. Just type ``make'' after applying the patch!

The modified kernel

• Linux 2.2 kernel: The source code for the kernel that serves as the basis for the Laplace kernel which records essential events.
• Laplace 0.8 Linux patch: The patch to the Linux 2.2.21 kernel to make it log its own events. Note that this patch includes a file named ``bochs.config'', which is the configuration file that you can use to build this kernel in a manner appropriate for running on a Bochs machine.
• Laplace 0.8 Linux kernel: A pre-compiled copy of the kernel. It does not use modules, so it can be installed as a stand-alone kernel image.

Reference handlers

• raw-reference-binary-to-text: A utility that reads a raw reference trace in its binary format (as emitted by a Laplace machine) and translates it into a text format.
• instruction-level-reduction: Reads a binary raw reference trace and performs difference encoding on each record before emitting it in a text format. Ideal for gathering instruction level traces where the output of this reference handler can be piped into a text compressor like gzip or bzip2.
• page-level-reduction v0.8.2: Reads a binary raw reference trace and performs SAD reduction, which eliminates a large number of superfluous references and leaves a sequence of references to pages (instead of byte addresses). This sequence is difference encoded and emitted in a text form and compressed with zlib, leaving a directory of trace files, one per task, in a format that gzip can read. These traces are intended for virtual memory simulations, and thanks to the lossy SAD reduction, can be orders of magnitude smaller than their instruction-level counterparts.

Merging post-processor

• Laplace-merge: The merging post-processor that reads a reference trace and a kernel trace and correlates the events in both. It reconstructs the state of processes, threads, and memory mappings at each moment, and is capable of producing a number of final trace formats that contain the unified information. Note that it is capable reading each of the reference trace formats produced by the reference handlers listed above.