Timing and Benchmarking

Timing

time()

time() function gets the system time in seconds since the epoch, with fairly high (typically, microsecond) resolution.

start_time = time()
# ...
elapsed_time = time() - start_time
println("Elapsed time: $elapsed_time seconds")

@elapsed

@elapsed is a macro to evaluate an expression, discarding the resulting value, instead returning the number of seconds it took to execute as a floating-point number.

elapsed_time = @elapsed begin
    # ...
end
println("Elapsed time: $elapsed_time seconds")

TimerOutputs.jl

TimerOutputs is a small Julia package that is used to generate formatted output from timings made in different sections of a program.

using TimerOutputs
const to = TimerOutput() # create a timer
# Define a function that needs to be timed
function compute_sum(n)
    sum = 0
    @timeit to "Loop over elements" for i in 1:n
        sum += i
    end
    return sum
end
@timeit to "Total computation" begin
    result1 = compute_sum(100_000)
    result2 = compute_sum(200_000)
    println("Result 1: ", result1)
    println("Result 2: ", result2)
    show(to)
end

Benchmarking

using BenchmarkTools
a = rand(100,100)
b = rand(100,100)
@btime begin
    c = $a + $b
end

A description of “$” can be found at stackoverflow.