Sodden - An Olden benchmarks cmake harness

Introduction

This is a CMake build harness for the Olden benchmarks.

The actual source files for each benchmark are not included, but use this instead.

Features

• Building of all 10 C programs of the suite
• Out-of-source builds thanks to cmake
• Capability to create LLVM bitcode files thanks to llvm-ir-cmake-utils and LLVM opt pass pipelines (see the config/pipelines subdirectory).
• Capability to configure and build any desired subset of the programs by using the corresponding configuration (see the suite_* files in the config subdirectory).

Requirements

• cmake 3.0.0 or later
• a sensible C compiler

How to use

1. git clone --recursive this repo and git clone the benchmark source repo.

2. Create symlinks to the src subdirectory of each benchmark program. This can be automated with the relevant script found in the utils/scripts/source_tree subdirectory of this repo, for example:

   create-symlink-bmk-subdir.sh -c suite_all.txt -s [path-to]/olden/ -t [path-to]/sodden/olden/ -l src

3. Create a directory for an out-of-source build and cd into it.

4. Run cmake and cmake --build . with that appropriate options. For examples on the various options have a look at the build scripts (provided for convenience) located in the utils/scripts/source_tree subdirectory.

5. Optionally, you can install the benchmarks by

   cmake -DCMAKE_INSTALL_PREFIX=[path-to-install] -P cmake_install.cmake

   Omitting CMAKE_INSTALL_PREFIX will use the ../install/ directory relative to the build directory.

Benchmark-specific configuration options

Timing

The harness defines a few macros, using the prefix OLDEN_ in the common/timing.h header, that allow measuring the execution duration of sections of code. This facility seems to have been present, but was stripped away at some point. Currently, these macros require a POSIX compliant system, so the specific detection is left to cmake with the use of the common/config.h.cmake generated header. On non-POSIX system the macros have dummy/empty alternatives.

Source language selection

Typically build tools for C/C++ projects detect the source file language by rules based on the file extension. This allows to invoke the corresponding compiler for each source file.

However, the programs of this benchmark suite are not very cleanly written, in terms of separation (and as much as this is possible by C and C++). So, since one the goals is to rejuvenate the source code and convert it to C++ while allowing this to happen independently, the detection of the source language per benchmark happens at the cmake level.

Automatic source language detection is set to occur per benchmark program like this:

1. By default the source language is set to C.
2. File globbing is used to gather all C (*.c) and C++ (*.cpp) source files.
3. If there is at least 1 C++ file, the source language is changed to C++.

So, in order to use the C++ compiler for a benchmark, you need to have at least a C++ source file in its source directory.

more TODO

How the harness works

For a general description on how this harness operates please have a look here.