FAQ

Building custom system image

NOTE: TTTX has been greatly improved since Julia 1.9 the notes below are mostly no longer relevant.

At the time of writing, loading Julia modules comes with high latency in addition to the the so called time-to-first-X (TTFX) delay related to time spent on compiling native code in each fresh Julia session.

Such delays can be completely eliminated by compiling a system image using the PackageCompiler.jl, which contain EDDPotentials.jl, EDDPotentialsTools.jl and all its dependencies. This can be done by simply following the documentation of the PackageCompiler.jl

For development environment this is a bit more complicated while the inconvenience of compiler latency is more pronounce due to frequent session restarts. In this case, a special system image needs to be created that includes all dependencies of EDDPotentials.jl and EDDPotentialsTools.jl, plus some commonly used tools (such as BenchmarkTools.jl and Revise), but not EDDPotentials.jl and EDDPotentialsTools.jl themselves. Create such system image, there is a sysimg.jl under the scripts folder that can used via:

julia --project=<some project with PackageCompiler installed> -e 'include("sysimg.jl");build()' 

This creates the system image file at ~/.julia/eddpdev.so. To launch julia with the system image:

julia -J ~/.julia/eddpdev.so

julia> "Flux" in [x.name for x in keys(Base.loaded_modules)]
true

One should note that any packages compiled into the system image is essentially frozen-in - their version cannot be changed by Pkg. Hence, the system image must be rebuilt after any update of the Manifest.toml.