Precompiling LanguageServer.runserver() with PrecompileTools.jl

After a conversation on Slack, with Tom McLaughlin, I decided to try adding some precompilation to LanguageServer.jl. Tom had noticed about 10 second lag in the execution of LanguageServer.runserver(). This is part of julia-vscode, so a speed up here would be quite beneficial.

Before the change, runserver() would take about 14 seconds to compile on my computer after each time the package is loaded.

julia> @time runserver()
 30.517983 seconds (6.45 M allocations: 370.912 MiB, 1.60% gc time, 46.59% compilation time)

julia> 30.517983*0.4659

After the change, runserver(), compilation takes 1.4 seconds.

julia> @time runserver()
 10.929685 seconds (3.77 M allocations: 198.920 MiB, 3.33% gc time, 12.61% compilation time)

julia> 10.929685 * 0.1261

Load time while running using LanguageServer increased from ~20 ms to ~550 ms. The compiled cache shared library went from 2.4 MB to 13 MB.

The substantive part of my change is as follows. Can you do better?

using PrecompileTools
@setup_workload begin
    iob = IOBuffer()
    @compile_workload begin
precompile(runserver, ())

There’s a lot to improve. Running this during precompilation involves network activity for one.

Here’s the pull request:

In case you missed the announcement, PrecompileTools.jl is the new name of SnoopPrecompile.jl.