How to eliminate JIT overhead in a Julia executable (with MWE)

Question

I'm using PackageCompiler hoping to create an executable that eliminates just-in-time compilation overhead.

The documentation explains that I must define a function julia_main to call my program's logic, and write a "snoop file", a script that calls functions I wish to precompile. My julia_main takes a single argument, the location of a file containing the input data to be analysed. So to keep things simple my snoop file simply makes one call to julia_main with a particular input file. So I'd hope to see the generated executable run nice and fast (no compilation overhead) when executed against that same input file.

But alas, that's not what I see. In a fresh Julia instance julia_main takes approx 74 seconds for the first execution and about 4.5 seconds for subsequent executions. The executable file takes approx 50 seconds each time it's called.

My use of the build_executable function looks like this:

julia> using PackageCompiler

julia> build_executable("d:/philip/source/script/julia/jsource/SCRiPTMain.jl",
                        "testexecutable",
                        builddir = "d:/temp/builddir4",
                        snoopfile = "d:/philip/source/script/julia/jsource/snoop.jl",
                        compile = "all",
                        verbose = true)

Questions:

1. Are the above arguments correct to achieve my aim of an executable with no JIT overhead?
2. Any other advice for me?

Here's what happens in response to that call to build_executable. The lines from Start of snoop file execution! to End of snoop file execution! are emitted by my code.

Julia program file:
  "d:\philip\source\script\julia\jsource\SCRiPTMain.jl"
C program file:
  "C:\Users\Philip\.julia\packages\PackageCompiler\CJQcs\examples\program.c"
Build directory:
  "d:\temp\builddir4"
Executing snoopfile: "d:\philip\source\script\julia\jsource\snoop.jl"
Start of snoop file execution!
┌ Warning: The 'control file' contains the key 'InterpolateCovariance' with value 'true' but that is not supported. Pass a value of 'false' or omit the key altogether.
└ @ ValidateInputs d:\Philip\Source\script\Julia\JSource\ValidateInputs.jl:685
Time to build model 20.058000087738037
Saving c:/temp/SCRiPT/SCRiPTModel.jls
Results written to c:/temp/SCRiPT/SCRiPTResultsJulia.json
Time to write file: 3620 milliseconds
Time in method runscript: 76899 milliseconds
End of snoop file execution!
[ Info: used 1313 out of 1320 precompile statements
Build static library "testexecutable.a":
  atexit_hook_copy = copy(Base.atexit_hooks) # make backup
# clean state so that any package we use can carelessly call atexit
empty!(Base.atexit_hooks)
Base.__init__()
Sys.__init__() #fix https://github.com/JuliaLang/julia/issues/30479
using REPL
Base.REPL_MODULE_REF[] = REPL
Mod = @eval module $(gensym("anon_module")) end
# Include into anonymous module to not polute namespace
Mod.include("d:\\\\temp\\\\builddir4\\\\julia_main.jl")
Base._atexit() # run all exit hooks we registered during precompile
empty!(Base.atexit_hooks) # don't serialize the exit hooks we run + added
# atexit_hook_copy should be empty, but who knows what base will do in the future
append!(Base.atexit_hooks, atexit_hook_copy)

Build shared library "testexecutable.dll":
  `'C:\Users\Philip\.julia\packages\WinRPM\Y9QdZ\deps\usr\x86_64-w64-mingw32\sys-root\mingw\bin\gcc.exe' --sysroot 'C:\Users\Philip\.julia\packages\WinRPM\Y9QdZ\deps\usr\x86_64-w64-mingw32\sys-root' -shared '-DJULIAC_PROGRAM_LIBNAME="testexecutable.dll"' -o testexecutable.dll -Wl,--whole-archive testexecutable.a -Wl,--no-whole-archive -std=gnu99 '-IC:\Users\philip\AppData\Local\Julia-1.2.0\include\julia' -DJULIA_ENABLE_THREADING=1 '-LC:\Users\philip\AppData\Local\Julia-1.2.0\bin' -Wl,--stack,8388608 -ljulia -lopenlibm -m64 -Wl,--export-all-symbols`
Build executable "testexecutable.exe":
  `'C:\Users\Philip\.julia\packages\WinRPM\Y9QdZ\deps\usr\x86_64-w64-mingw32\sys-root\mingw\bin\gcc.exe' --sysroot 'C:\Users\Philip\.julia\packages\WinRPM\Y9QdZ\deps\usr\x86_64-w64-mingw32\sys-root' '-DJULIAC_PROGRAM_LIBNAME="testexecutable.dll"' -o testexecutable.exe 'C:\Users\Philip\.julia\packages\PackageCompiler\CJQcs\examples\program.c' testexecutable.dll -std=gnu99 '-IC:\Users\philip\AppData\Local\Julia-1.2.0\include\julia' -DJULIA_ENABLE_THREADING=1 '-LC:\Users\philip\AppData\Local\Julia-1.2.0\bin' -Wl,--stack,8388608 -ljulia -lopenlibm -m64`
Copy Julia libraries to build directory:
  7z.dll
  BugpointPasses.dll
  libamd.2.4.6.dll
  libamd.2.dll
  libamd.dll
  libatomic-1.dll
  libbtf.1.2.6.dll
  libbtf.1.dll
  libbtf.dll
  libcamd.2.4.6.dll
  libcamd.2.dll
  libcamd.dll
  libccalltest.dll
  libccolamd.2.9.6.dll
  libccolamd.2.dll
  libccolamd.dll
  libcholmod.3.0.13.dll
  libcholmod.3.dll
  libcholmod.dll
  libclang.dll
  libcolamd.2.9.6.dll
  libcolamd.2.dll
  libcolamd.dll
  libdSFMT.dll
  libexpat-1.dll
  libgcc_s_seh-1.dll
  libgfortran-4.dll
  libgit2.dll
  libgmp.dll
  libjulia.dll
  libklu.1.3.8.dll
  libklu.1.dll
  libklu.dll
  libldl.2.2.6.dll
  libldl.2.dll
  libldl.dll
  libllvmcalltest.dll
  libmbedcrypto.dll
  libmbedtls.dll
  libmbedx509.dll
  libmpfr.dll
  libopenblas64_.dll
  libopenlibm.dll
  libpcre2-8-0.dll
  libpcre2-8.dll
  libpcre2-posix-2.dll
  libquadmath-0.dll
  librbio.2.2.6.dll
  librbio.2.dll
  librbio.dll
  libspqr.2.0.9.dll
  libspqr.2.dll
  libspqr.dll
  libssh2.dll
  libssp-0.dll
  libstdc++-6.dll
  libsuitesparseconfig.5.4.0.dll
  libsuitesparseconfig.5.dll
  libsuitesparseconfig.dll
  libsuitesparse_wrapper.dll
  libumfpack.5.7.8.dll
  libumfpack.5.dll
  libumfpack.dll
  libuv-2.dll
  libwinpthread-1.dll
  LLVM.dll
  LLVMHello.dll
  zlib1.dll
All done

julia> 

EDIT

I was afraid that creating a minimal working example would be hard, but it was straightforward:

TestBuildExecutable.jl contains:

module TestBuildExecutable

Base.@ccallable function julia_main(ARGS::Vector{String}=[""])::Cint
    @show sum(myarray())
    return 0
end

#Function which takes approx 8 seconds to compile. Returns a 500 x 20 array of 1s
function myarray()
    [1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1;
     1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1;

# PLEASE EDIT TO INSERT THE MISSING 496 LINES, EACH IDENTICAL TO THE LINE ABOVE!

     1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1;
     1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1]
end

end #module

SnoopFile.jl contains:

module SnoopFile

currentpath = dirname(@__FILE__)
push!(LOAD_PATH, currentpath)
unique!(LOAD_PATH)

using TestBuildExecutable

println("Start of snoop file execution!")
TestBuildExecutable.julia_main()
println("End of snoop file execution!")

end # module

In a fresh Julia instance, julia_main takes 8.3 seconds for the first execution and half a millisecond for the second execution:

julia> @time TestBuildExecutable.julia_main()
sum(myarray()) = 10000
  8.355108 seconds (425.36 k allocations: 25.831 MiB, 0.06% gc time)
0

julia> @time TestBuildExecutable.julia_main()
sum(myarray()) = 10000
  0.000537 seconds (25 allocations: 82.906 KiB)
0

So next I call build_executable:

julia> using PackageCompiler

julia> build_executable("d:/philip/source/script/julia/jsource/TestBuildExecutable.jl",
                       "testexecutable",
                       builddir = "d:/temp/builddir15",
                       snoopfile = "d:/philip/source/script/julia/jsource/SnoopFile.jl",
                       verbose = false)
Julia program file:
  "d:\philip\source\script\julia\jsource\TestBuildExecutable.jl"
C program file:
  "C:\Users\Philip\.julia\packages\PackageCompiler\CJQcs\examples\program.c"
Build directory:
  "d:\temp\builddir15"
Start of snoop file execution!
sum(myarray()) = 10000
End of snoop file execution!
[ Info: used 79 out of 79 precompile statements
All done

Finally, in a Windows Command Prompt:

D:\temp\builddir15>testexecutable
sum(myarray()) = 1000

D:\temp\builddir15>

which took (by my stopwatch) 8 seconds to run, and it takes 8 seconds to run every time it's executed, not just the first time. This is consistent with the executable doing a JIT compile every time it's run, but the snoop file is designed to avoid that!

Version information:

julia> versioninfo()
Julia Version 1.2.0
Commit c6da87ff4b (2019-08-20 00:03 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, skylake)
Environment:
  JULIA_NUM_THREADS = 8
  JULIA_EDITOR = "C:\Users\Philip\AppData\Local\Programs\Microsoft VS Code\Code.exe"

Answer 1

Looks like you are using Windows.

At some point PackageCompiler.jl will be mature for Windows at which you can try it.

Answer 2

The solution was indeed to wait for progress on PackageCompilerX, as suggested by @xiaodai.

On 10 Feb 2020 what was formerly PackageCompilerX became a new (version 1.0 of) PackageCompiler, with a significantly changed API, and more thorough documentation.

In particular, the MWE above (mutated for the new API to PackageCompiler) now works correctly without any JIT overhead.