SPNGT

SPNGT is a benchmarking and testing utility for libspng, libpng, stb_image, lodepng and wuffs.

This is a standalone project, it is also used as a subproject in libspng for benchmarking and to host non-libspng code.

Dependencies

• Meson 0.55.0 or later
• Git LFS for downloading the benchmark images

Meson will fall back to using wraps if the following are not found on the system:

• spng
• libpng
• stb_image
• lodepng
• stb
• zlib
• wuffs
• Lua

Creating a build

# Add --default-library=static on Windows
meson build --buildtype=release

Running the benchmark

cd build
meson test -t 0 --benchmark --suite decode #or encode
cat meson-logs/benchmarklog.txt

ninja benchmark runs all tests.

Compile with Profile-guided optimization (PGO)

meson configure -Db_pgo=generate
ninja benchmark
meson configure -Db_pgo=use
ninja benchmark
cat meson-logs/benchmarklog.txt

Notes

The benchmarks try to exclude system overhead by preloading the PNG into a buffer, this provides better feedback for development, real world performance may not be the same but has been accurate been so far.

Command-line interface

Read one file and print the best decode/encode time for each library

$ spngt IMAGE.png
$ spngt IMAGE.png enc # For encode benchmarks
$ spngt info # Print library versions and other information

Or execute a lua script, the rest of the arguments will be exposed through the arg global

$ spngt main.lua SUITE_NAME FOO.png BAR.png #main.lua takes a base filename (SUITE_NAME) for its output files

Running experiments

Results are written to .csv files in the build directory, see main.lua.

meson test -t 0 --benchmark tango
meson test -t 0 --benchmark kodak
meson test -t 0 --benchmark mixed