$ julia -t6 -q
julia> x = zeros(100);

julia> @time for i in x
           i
       end
  0.007487 seconds (4.00 k allocations: 204.148 KiB, 98.58% compilation time: 41% of which was recompilation)

julia> @time Threads.@threads for i in x
           i
       end
  0.046984 seconds (43.01 k allocations: 2.156 MiB, 7 tasks scheduled, 156.00% compilation time: 6% of which was recompilation)

julia> @time for i in x
           Threads.@spawn i
       end
  0.010576 seconds (5.74 k allocations: 295.383 KiB, 100 tasks scheduled, 96.17% compilation time: 60% of which was recompilation)