using BenchmarkTools
@benchmark using ModuleName
Option 1: Precompiling Modules
One way to speed up the startup time in Julia when adding modules is to precompile them. Julia has a built-in mechanism for precompiling modules, which can significantly reduce the time it takes to load them.
To precompile a module, you can use the `precompile` function. For example, if you want to precompile the `ModuleName` module, you can do:
precompile(ModuleName)
This will precompile the `ModuleName` module and store the precompiled code in the `~/.julia/compiled` directory. The next time you start Julia and load the `ModuleName` module, it will be loaded much faster.
Option 2: Using PackageCompiler
Another option to speed up the startup time in Julia is to use the `PackageCompiler` package. This package allows you to create a custom system image that includes all the modules you need, so they are already loaded when you start Julia.
To use `PackageCompiler`, you first need to install it by running the following command in the Julia REPL:
using Pkg
Pkg.add("PackageCompiler")
Once `PackageCompiler` is installed, you can create a custom system image by running the following code:
using PackageCompiler
create_sysimage([:ModuleName1, :ModuleName2], sysimage_path="custom_sysimage.so")
This will create a custom system image named `custom_sysimage.so` that includes the `ModuleName1` and `ModuleName2` modules. To start Julia using this custom system image, you can run:
julia --sysimage custom_sysimage.so
Starting Julia with this custom system image will load the specified modules much faster.
Option 3: Using PackageCompiler and Precompiling
A combination of the previous two options can provide even better startup time improvements. You can precompile the modules you need and then create a custom system image that includes the precompiled code.
To do this, first precompile the modules using the `precompile` function as described in Option 1. Then, create a custom system image that includes the precompiled code by running the following code:
using PackageCompiler
create_sysimage([:ModuleName1, :ModuleName2], sysimage_path="custom_sysimage.so", precompile_execution_file="precompile.jl")
In this case, the `precompile_execution_file` argument specifies a Julia script that will be executed during the creation of the custom system image. This script should contain the `precompile` function calls for the modules you want to precompile.
Starting Julia with this custom system image will load the specified modules much faster, as the precompiled code is already included in the system image.
After trying all three options, it is difficult to determine which one is better as it depends on the specific use case and requirements. Option 1 is the simplest and requires no additional packages, but it may not provide as much improvement in startup time compared to the other options. Option 2 and 3 require the installation of the `PackageCompiler` package and additional steps to create a custom system image, but they can provide significant improvements in startup time, especially when dealing with large and complex modules.
