Benchmark pull request introduced to LinearMaps

benchmark_LinearMaps_change.jl

using BenchmarkTools
using Statistics
using Plots

 _flags(A::Array) = unsafe_load(convert(Ptr{UInt16}, pointer_from_objref(A)), 9)
_isshared(A::Array) = !(_flags(A) & 0x4000 == 0x0000)

function create_and_resize_flag(n)
    a = Array{Float64}(undef, 1000)
    if !_isshared(a)
        resize!(a, n)
    else
        @warn("shared")
        a = Array{Float64}(undef, n)
    end
    return
end

function create_and_resize_try(n)
    a = Array{Float64}(undef, 1000)
    try
        resize!(a, n)
    catch err
        @warn(err)
    end
    return
end
function create_and_resize(n)
    a = Array{Float64}(undef, 1000)
    resize!(a, n)
    return
end
function create(n)
    a = Array{Float64}(undef, n)
    return
end

create_resize_flag_t = Float64[]
create_resize_try_t = Float64[]
create_resize_t = Float64[]
create_t = Float64[]
t1 = minimum(@benchmark create(1000)).time
lengths = round.(Int, 10 .^ (1:0.5:5.5))
for i in lengths
    println(i)
    t = @benchmark create_and_resize_flag($i)
    push!(create_resize_flag_t, median(t).time - t1)
    t = @benchmark create_and_resize_try($i)
    push!(create_resize_try_t, median(t).time - t1)
    t = @benchmark create_and_resize($i)
    push!(create_resize_t, median(t).time - t1)
    t = @benchmark create($i)
    push!(create_t, median(t).time)
end

plot(lengths, create_resize_try_t, label="Resize and try", lw=3, xscale = :log10, yscale = :log10)

plot!(lengths, create_resize_t, label="Resize", lw=3, xscale = :log10, yscale = :log10)
plot!(lengths, create_t, label="Create", lw=3, xscale = :log10, yscale = :log10)
plot!(lengths, create_resize_flag_t, style=:dot, label="Resize by flag", lw=3, xscale = :log10, yscale = :log10)
plot!([1_000, 1_000], [10, 10^5], style=:dash, color="black", lw=1, label="Resize from here", xscale = :log10, yscale = :log10, xlabel="Length", ylabel="Time [ns]", legend=:bottomright)
savefig("benchmark.png")