Julia in Colab

[roflmaostc]

You are not synchronizing the kernels, hence I believe you measure only the kernel launch. You need to CUDA.@sync the CUDA call.

using Pkg
Pkg.add("CUDA")
Pkg.add("BenchmarkTools")
using Plots, CUDA, BenchmarkTools

pMax = 8
powerVector = 1:pMax
timeVectorCPU = Vector{Float16}(undef, pMax)
timeVectorGPU = Vector{Float16}(undef, pMax)

for p in powerVector
    n = 10^p
    xCPU, yCPU = (ones(n), ones(n))
    xGPU, yGPU = (cu(xCPU), cu(yCPU))

    timeVectorCPU[p] = @belapsed $xCPU + $yCPU
    timeVectorGPU[p] = @belapsed CUDA.@sync $xGPU + $yGPU
end

timeVectorCPU |> display
timeVectorGPU |> display

plot(
    10 .^ powerVector, 
    [timeVectorCPU timeVectorGPU], 
    label = ["CPU" "GPU"], 
    title = "CPU vs GPU",
    xscale = :log10,
    yscale = :log10,
    ylabel = "Elapsed time [s]",
    fmt = :png
)