When I run the following script:
#!/usr/bin/julia
using ArgParse
#using PyPlot
#using FortranFiles
#using BenchmarkTools
#using DiffEqBase
#using Parameters
#using LinearMaps
#using LineSearches
function parse_commandline()
    s = ArgParseSettings()
    @add_arg_table s begin
        "--ex1"
            help = "Run example 1."
            action = :store_true
        "--ex2"
            help = "Run example 2."
            action = :store_true
        "--ex3"
            help = "Run example 3."
            action = :store_true
        "--plot", "-p"
            help = "Plotting ..."
            action = :store_true
    end
    return parse_args(s)
end
function main()
    parsed_args = parse_commandline()
    println("Parsed args:")
    for (arg,val) in parsed_args
        println("  $arg  =>  $val")
    end
end
main()
it takes about 2 sec to startup.
$ ./test_parset.jl
Parsed args:
  ex1  =>  false
  ex2  =>  false
  plot  =>  false
  ex3  =>  false
real	0m1.987s
user	0m1.921s
sys	0m0.228s
If now I uncomment the lines #using ..., I get a startup time 3 times slower.
Parsed args:
  ex1  =>  false
  ex2  =>  false
  plot  =>  false
  ex3  =>  false
real	0m6.402s
user	0m6.071s
sys	0m0.332s
Is this normal? Can I improve the speed somehow?