While waiting for general improvements in compile and load times (cf. comment in Roadmap for a faster time-to-first-plot? - #199 by ChrisRackauckas), what else can we do to improve the user experience for the packages we develop?
Here is my list of ideas, along with all the problems I encounter. I’d be happy to hear your feedback and suggestions. 
1. Analyse what’s going wrong
I struggle to reproduce the analysis of @ChrisRackauckas https://github.com/JuliaPlots/Plots.jl/pull/2157 on a package of mine. I ran
using Profile, ProfileView
Profile.clear()
@profile using MyPackage
ProfileView.view(C=true)
but I find it really hard to read that graph. How are you getting those exact information on how long it takes to load what part of the code?
2. Provide a manual for PackageCompiler tailored to your package
My package’s tests are basically non-existant right now:
# test/runtests.jl
using MyPackage
But having them allows me to use the simpler interface of PackageCompiler.jl’s compile_incremental:
using PackageCompiler
compile_incremental(:MyPackage)
However, the above process fails. At first because it didn’t know my package in the project PackageCompiler.jl creates, so I ]deved it into the default environment/project, but that didn’t help much:
...
[ Info: used 161 out of 161 precompile statements
┌ Info: activating new environment at ~/.julia/packages/PackageCompiler/CJQcs/packages/Project.toml.
└ @ Pkg.API /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.0/Pkg/src/API.jl:605
Updating registry at `~/.julia/registries/General`
Updating git-repo `https://github.com/JuliaRegistries/General.git`
fatal: error thrown and no exception handler available.
ErrorException("Task cannot be serialized")
...
jl_save_system_image_to_stream at /buildworker/worker/package_linux64/build/src/staticdata.c:1273
jl_create_system_image at /buildworker/worker/package_linux64/build/src/staticdata.c:1378
jl_write_compiler_output at /buildworker/worker/package_linux64/build/src/precompile.c:68
jl_atexit_hook at /buildworker/worker/package_linux64/build/src/init.c:233
main at /buildworker/worker/package_linux64/build/ui/repl.c:234
__libc_start_main at /build/glibc-LK5gWL/glibc-2.23/csu/../csu/libc-start.c:291
_start at /scratch/jschulze/julia-1.0.5/bin/julia (unknown line)
ERROR: failed process: Process(`/scratch/jschulze/julia-1.0.5/bin/julia --optimize=3 --output-o=/home/jschulze/.julia/packages/PackageCompiler/CJQcs/sysimg/sys.a -g1 --track-allocation=none --startup-file=no --code-coverage=none --history-file=yes --inline=yes --math-mode=ieee --handle-signals=yes --warn-overwrite=no --compile=yes --depwarn=yes --cpu-target=native --track-allocation=none --sysimage-native-code=yes --sysimage=/scratch/jschulze/julia-1.0.5/lib/julia/sys.so -g1 --compiled-modules=yes --optimize=2 /home/jschulze/.julia/packages/PackageCompiler/CJQcs/sysimg/run_julia_code.jl`, ProcessExited(1)) [1]
Stacktrace:
[1] error(::String, ::Base.Process, ::String, ::Int64, ::String) at ./error.jl:42
[2] pipeline_error at ./process.jl:705 [inlined]
[3] #run#505(::Bool, ::Function, ::Cmd) at ./process.jl:663
[4] run at ./process.jl:661 [inlined]
[5] #run_julia#1 at /home/jschulze/.julia/packages/PackageCompiler/CJQcs/src/compiler_flags.jl:225 [inlined]
[6] #run_julia at ./none:0 [inlined]
[7] #compile_incremental#62(::Bool, ::Bool, ::Bool, ::Nothing, ::Function, ::String, ::String) at /home/jschulze/.julia/packages/PackageCompiler/CJQcs/src/incremental.jl:137
[8] compile_incremental at /home/jschulze/.julia/packages/PackageCompiler/CJQcs/src/incremental.jl:134 [inlined]
[9] #compile_incremental#63 at /home/jschulze/.julia/packages/PackageCompiler/CJQcs/src/incremental.jl:177 [inlined]
[10] compile_incremental(::Symbol) at /home/jschulze/.julia/packages/PackageCompiler/CJQcs/src/incremental.jl:176
[11] top-level scope at none:0
What am I missing?
Is this the wrong way?
3. Your suggestions
[to be continued]