Benchee reduction counting example

bench.exs

list = Enum.to_list(1..10_000)
map_fun = fn i -> [i, i * i] end

Benchee.run(
  %{
    "flat_map" => fn -> Enum.flat_map(list, map_fun) end,
    "map.flatten" => fn -> list |> Enum.map(map_fun) |> List.flatten() end
  },
  reduction_time: 2
)

output

Operating System: Linux
CPU Information: AMD Ryzen 9 5900X 12-Core Processor
Number of Available Cores: 24
Available memory: 31.27 GB
Elixir 1.13.3
Erlang 24.2.1

Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
reduction time: 2 s
parallel: 1
inputs: none specified
Estimated total run time: 18 s

Benchmarking flat_map ...
Benchmarking map.flatten ...

Name                  ips        average  deviation         median         99th %
flat_map           3.52 K      283.95 μs    ±10.98%      279.09 μs      500.28 μs
map.flatten        2.26 K      441.58 μs    ±20.43%      410.51 μs      680.60 μs

Comparison: 
flat_map           3.52 K
map.flatten        2.26 K - 1.56x slower +157.64 μs

Reduction count statistics:

Name        Reduction count
flat_map            65.01 K
map.flatten        124.52 K - 1.92x reduction count +59.51 K

**All measurements for reduction count were the same**