outline length assert in default_rng(tid)

[KristofferC]

Ref #34216

Benchmark

# export JULIA_NUM_THREADS=4
using BenchmarkTools, Random, Base.Threads

function par_pi(n::Int)
    hits = zeros(Int, nthreads())
    @threads for i in 1:n
        x, y = rand(), rand()
        hits[threadid()] += (x^2 + y^2 <= 1)
    end

    4.0 * sum(hits) / n
end
@btime par_pi(10_000_000)

master:

168.895 ms (24 allocations: 2.83 KiB)

PR:

 83.366 ms (24 allocations: 2.83 KiB)

[vtjnash]

Good find! I thought I had already beat on this as much as was possible.

[jebej]

Is the outlining trick for fixing performance when something throws an exception something that will be fixed? It seems unsustainable to do this in every single case.

[Keno]

It's a micro-optimization that doesn't usually matter. That said, it would be nice to do this automatically eventually.