bench_dot.jl

#!/usr/bin/env julia

function sdot(n, x, y)
    a = 0
    @inbounds @fastmath @simd for i=1:n
        a += x[i]*y[i]   
    end
    a
end

function pdot(n, x, y)
    @fastmath @parallel (+) for i=1:n
        x[i]*y[i]
    end
end

n = 10000000
x = [ 1. for i=1:n]
y = [ i for i=1.:n]


println("Naive Julia")
println(@sprintf("  %.2f", sdot(n, x, y)))
@time for i=1:3
    sdot(n, x, y)
end

println("\nNative Julia")
println(@sprintf("  %.2f", dot(x, y)))
@time for i=1:3
    dot(x, y)
end

println("\nIdiomatic parallel Julia")
println(@sprintf("  %.2f", pdot(n, x, y)))
@time for i=1:3
    pdot(n, x, y)
end