# BencheeDsl
[](https://hex.pm/packages/benchee_dsl)
[](https://github.com/hrzndhrn/benchee_dsl/actions)
[](https://coveralls.io/github/hrzndhrn/benchee_dsl)
[](https://github.com/hrzndhrn/benchee_dsl/blob/main/LICENSE.md)
`BencheeDsl` offers a DSL to write benchmarks for [Benchee](https://github.com/bencheeorg/benchee)
in an ExUnit style. For more informations to benchmarks and interpretation of
the results see the [Benchee documentation](https://hexdocs.pm/benchee/readme.html).
[](https://livebook.dev/run?url=https%3A%2F%2Fgithub.com%2Fhrzndhrn%2Fbenchee_dsl%2Fblob%2Fmain%2Fbenchee_dsl.livemd)
## Installation
First, add `benchee` and `benchee_dsl` to your `mix.exs` dependencies:
```elixir
def deps do
[
{:benchee, "~> 1.1", only: :dev},
{:benchee_dsl, "~> 0.5", only: :dev}
]
end
```
Then, update your dependencies:
```shell
$ mix deps.get
```
## Usage
Generate the `bench` directory, the `bench/benchee_helper.exs`, and the example
`bench/example_bench.exs` with:
```
$ mix bench.gen
Create directory bench.
Write 'bench/benchee_helper.exs'.
Write 'bench/example_bench.exs'.
```
Start the benchmark with:
```
$ mix bench
...
Benchmarking flat_map with input Bigger...
Benchmarking flat_map with input Medium...
Benchmarking flat_map with input Small...
Benchmarking map_flatten with input Bigger...
Benchmarking map_flatten with input Medium...
Benchmarking map_flatten with input Small...
...
```
## Writing benchmarks
In the standard configuration the benchmarks are stored in the `bench`
directory. The benchmarks are saved in a file with the ending `_bench.exs`.
The example benchmark:
```elixir
defmodule ExampleBench do
use BencheeDsl.Benchmark
config time: 3, pre_check: true
inputs %{
"Small" => Enum.to_list(1..1_000),
"Medium" => Enum.to_list(1..10_000),
"Bigger" => Enum.to_list(1..100_000)
}
defp map_fun(i), do: [i, i * i]
job flat_map(input) do
Enum.flat_map(input, &map_fun/1)
end
job map_flatten(input) do
input |> Enum.map(&map_fun/1) |> List.flatten()
end
end
```
### Adding a formatter
The next example uses the formatter [`benchee_markdown`](https://hex.pm/packages/benchee_markdown)
```elixir
defmodule ExampleBench do
use BencheeDsl.Benchmark
config time: 1
formatter Benchee.Formatters.Markdown,
file: Path.expand("example.md", __DIR__),
description: """
Bla bla bla ...
"""
inputs %{
"Small" => Enum.to_list(1..1_000),
"Medium" => Enum.to_list(1..10_000),
"Bigger" => Enum.to_list(1..100_000)
}
defp map_fun(i), do: [i, i * i]
job flat_map(input) do
Enum.flat_map(input, &map_fun/1)
end
job map_flatten(input) do
input |> Enum.map(&map_fun/1) |> List.flatten()
end
end
```
### Inputs with do block
```elixir
defmodule ExampleBench do
use BencheeDsl.Benchmark
config time: 1
inputs do
data = data.json |> File.read!() |> Jason.decode()
%{
"Small" => Map.get(data, "small"),
"Medium" => Map.get(data, "medium"),
"Bigger" => Map.get(data, "bigger")
}
end
defp map_fun(i), do: [i, i * i]
job flat_map(input) do
Enum.flat_map(input, &map_fun/1)
end
job map_flatten(input) do
input |> Enum.map(&map_fun/1) |> List.flatten()
end
end
```
### Capture a job
Jobs can be captrured. In this case, the input must be a list with
the length of the function's arity. Note that the next example does not only
measueres `flat-map` and `map-flatten` but also `Enum.to_list`.
```elixir
defmodule Foo do
def flat_map(a, b) do
a |> data(b) |> Enum.flat_map(&map_fun/1)
end
def map_flatten(a, b) do
a |> data(b) |> Enum.map(&map_fun/1) |> List.flatten()
end
defp data(a, b), do: Enum.to_list(a..b)
defp map_fun(i), do: [i, i * i]
end
defmodule CaptureBench do
use BencheeDsl.Benchmark
inputs %{
"small" => [1, 100],
"medium" => [1, 10_000],
"bigger" => [1, 100_000]
}
job &Foo.map_flatten/2
job &Foo.flat_map/2
end
```
### Hooks
`BencheeDsl` accepts the tags
* `@before_scenario`
* `@before_each`
* `@after_each`
* `@after_each`
for a `job`. Each of this functions are accepting a function
with an arity of zero or one.
Global hooks are defined with the macros:
* `BencheeDsl.Benchmark.before_scenario/2`
* `BencheeDsl.Benchmark.before_each/2`
* `BencheeDsl.Benchmark.after_each/2`
* `BencheeDsl.Benchmark.after_scenario/2`
See the Benchee documentation for [hooks](https://github.com/bencheeorg/benchee#hooks-setup-teardown-etc)
for more informations.
The following example can be found at `example/sets`. The original benchmark
can be found at [josevalim/set_bench](https://github.com/josevalim/sets_bench).
```elixir
defmodule AddBench do
use BencheeDsl.Benchmark
inputs do
small = 1..10
medium = 1..1_000
large = 1..100_000
small_int_list = Enum.to_list(small)
medium_int_list = Enum.to_list(medium)
large_int_list = Enum.to_list(large)
small_bin_list = Enum.map(small, fn _ -> :crypto.strong_rand_bytes(10) end)
medium_bin_list = Enum.map(medium, fn _ -> :crypto.strong_rand_bytes(10) end)
large_bin_list = Enum.map(large, fn _ -> :crypto.strong_rand_bytes(10) end)
%{
"small eq int" => [15, small_int_list],
"medium eq int" => [1500, medium_int_list],
"large eq int" => [150_000, large_int_list],
"small eq bin" => [:crypto.strong_rand_bytes(10), small_bin_list],
"medium eq bin" => [:crypto.strong_rand_bytes(10), medium_bin_list],
"large eq bin" => [:crypto.strong_rand_bytes(10), large_bin_list]
}
end
@before_scenario fn [arg1, arg2] -> [arg1, :gb_sets.from_list(arg2)] end
job &:gb_sets.add_element/2
@tag :skip
@before_scenario fn [arg1, arg2] -> [arg1, :sets.from_list(arg2)] end
job &:sets.add_element/2
@before_scenario fn [arg1, arg2] -> [arg1, :ordsets.from_list(arg2)] end
job &:ordsets.add_element/2
end
```
### Setup and exit
```elixir
defmodule ExampleBench do
use BencheeDsl.Benchmark
require Logger
setup do
Logger.info("Starting benchmark")
on_exit fn ->
Logger.info("Ready.")
end
end
config time: 1
inputs %{
"Small" => Enum.to_list(1..1_000),
"Medium" => Enum.to_list(1..10_000),
"Bigger" => Enum.to_list(1..100_000)
}
defp map_fun(i) [i, i * i]
job flat_map(input) do
Enum.flat_map(input, &map_fun/1)
end
job map_flatten(input) do
input |> Enum.map(&map_fun/1) |> List.flatten()
end
end
```
