Precompilation/recompilation - what's going on?

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1

Hey folks,

I’m working on improving time to first X in Term.jl by precompilation etc, but it’s not a tool I’m super familiar with these things so I was hoping someone might give me some advice. For reference, I’ve red some of the blog posts out there and the docs for SnoopCompile.jl

I’m using SnoopPrecompile.jl to pre-compile code for a high-level constructor Panel.
If I run:

using Term
@time Panel(txt);

without any precompilation:

  2.044457 seconds (6.98 M allocations: 365.009 MiB, 14.36% gc time, 99.91% compilation time)

with:

1.017123 seconds (1.02 M allocations: 52.379 MiB, 1.67% gc time, 99.89% compilation time: 88% of which was recompilation)

Obviously an improvement, but why is so much time still being spent re-compiling a lot of stuff?

In my pre-compilation code I have:

 @precompile_setup begin
    @precompile_all_calls begin
        Panel(txt);
    end
end

so I’m calling exactly the same thing that I am then running again, why is it being recompiled?

From what I can gather online re-compilation is usually related to methods invalidation, but given that I’m not defining any new methods there, why are they getting invalidated? Also:

invalidations = @snoopr begin
    Panel(txt);
end

println("Num. invalidated methods: ", length(uinvalidated(invalidations)))

reports no methods invalidation.

Looking at inference with @snoopi_deep seems to suggest that inference is not a main issue either:

image
image1582×1106 61.5 KB

So, sorry for the potentially dumb question, but can someone explain to me how running the same function that I’ve pre-compiled triggers novel compilation? Also all subsequent calls to Panel(txt) after the first will not cause re-compilation.

Thank you,
Federico

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2

what version of Julia are you on? try nightly?

3

Thanks for getting back to me!

julia 1.8.3. Okay I can try, but wouldn’t that mean that Term.jl users with Julia 1.8.3 would experience the same issues?

4

yeah.

Because the root cause just very recently got improved:

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