You may know that several of us have been hard at work stamping out invalidations as a way of reducing Julia’s latency. Kristoffer Carlsson and I thought it might be fun to have a contest to do the opposite: see who can come up with truly horrendous methods that obliterate almost everything …

Turns out the BitInteger union is not needed. I was starting to feel that using Union Types might even have to become its own category, as I was building larger and larger ones to get more invalidations with a single method. But this is just as effective with convert: julia> using SnoopCompileCore …

Some i had high hopes for but that didn’t work out: Redefining Expr: _ _ _ _(_)_ | Documentation: https://docs.julialang.org (_) | (_) (_) | _ _ _| |_ __ _ | Type "?" for help, "]?" for Pkg help. | | | | | | |/ _` | | | | |_| | | | (_| | | Vers…

Does changing macros effect code that’s already defined?

No, changing a macro shouldn’t change anything for already applied macro, only future use. There might be exceptions, i.e. code that uses eval.

[image] oxinabox: I thought this should invalidate a bunch of things that otherwise wouldn’t be invalidatable, but seems not to have. Redefining a macro doesn’t have any effect on already-evaluated uses of the macro—the current meaning of the macro is used at parse time and after that there’s…

Today, I learned. Thinking about it, yes, that makes sense.

If these macros called some auxiliary inner function (inside the methods they modify) that could be invalidated, then this could work. But I do not know if it is the case (would guess no).

No because that still only affects future macro expansions: code that’s already been order and macro-expanded will not be released and expanded.

Just to clarify, I meant something like: @my_macro args expands to my_aux_f(args...) inside the method body of a function outer, so changing function my_aux_f (not macro my_macro) could invalidate the method outer. Having a programmer write the call to my_aux_f and a macro to do the same has indisti…

Yikes, realized I forgot to announce the results on Friday. To evaluate the submissions, I tested each using a script that I executed from the linux prompt to ensure there weren’t differences in my typing at the REPL (since hitting certain keys can force the compilation of new methods). In a couple …

A playful competition: who can define a method that invalidates the most code?

Tooling

DNF October 6, 2020, 11:05am 42

I believe this is related to the push towards fixing invalidations: Finding and fixing invalidations: now, everyone can help reduce time-to-first-plot

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Case Study: Method Invalidations caused by Pkg.jl with Julia 1.11 Internals & Design method-invalidation	13	1613	January 23, 2024
Invalidations findings (from a GMT case) General Usage performance	64	2238	January 12, 2023
Potential performance regressions in Julia 1.8 for special un-precompiled type dispatches and how to fix them Performance performance	25	3617	October 4, 2022
Understanding precompilation and its limitations (reducing latency) Internals & Design precompilation	13	2769	December 31, 2020
Blog post: Julia's latency: Past, present and future Community	33	2505	April 20, 2023

A playful competition: who can define a method that invalidates the most code?

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