Created
February 13, 2022 18:44
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Calling a simple NIF function every 0.1 seconds two times in a row results in different latency
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| defmodule Test.NativeProcessor.Lib do | |
| @moduledoc false | |
| @on_load :load_nifs | |
| def load_nifs do | |
| path = Application.app_dir(:test, "priv/native") |> String.to_charlist() | |
| :erlang.load_nif(path, 0) | |
| end | |
| def orders() do | |
| exit(:nif_not_loaded) | |
| end | |
| end | |
| defmodule Test.NativeProcessor.Client do | |
| @moduledoc false | |
| alias Test.NativeProcessor.Lib | |
| @impl true | |
| def orders(), do: Lib.orders() | |
| end | |
| defmodule Test.Server do | |
| use GenServer | |
| alias Test.NativeProcessor.Client | |
| def init(init_arg) do | |
| send(self(), :orders) | |
| {:ok, init_arg} | |
| end | |
| @impl true | |
| def handle_info(:orders, state) do | |
| orders() | |
| {:noreply, state} | |
| end | |
| defp orders() do | |
| timeit(:first, fn -> Client.orders() end) | |
| timeit(:second, fn -> Client.orders() end) | |
| Process.send_after(self(), :orders, 100) | |
| end | |
| defp now(), do: System.monotonic_time() | |
| defp timeit(name, f) do | |
| s = now() | |
| r = f.() | |
| e = now() | |
| IO.puts( | |
| "Calling a function #{inspect(name)} took #{inspect(System.convert_time_unit(e - s, :native, :nanosecond))} nsec" | |
| ) | |
| r | |
| end | |
| end | |
| defmodule Test.Main do | |
| @moduledoc false | |
| use Application | |
| @impl true | |
| def start(_type, _args) do | |
| GenServer.start_link(Test.Server, []) | |
| end | |
| end |
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| CXX ?= g++ | |
| ERLANG_PATH = $(shell erl -eval 'io:format("~s", [lists:concat([code:root_dir(), "/erts-", erlang:system_info(version), "/include"])])' -s init stop -noshell) | |
| OBJECTS = $(patsubst c_libs/%.cpp,build/%.o,$(wildcard c_libs/*.cpp)) | |
| all: priv/native.so | |
| dirs: | |
| mkdir -p build | |
| clean: | |
| rm -rf priv/native.so build | |
| priv/native.so: $(OBJECTS) | dirs | |
| echo $(OBJECTS) | |
| $(CXX) -Ofast -shared -fdiagnostics-color=always -o $@ $^ | |
| build/%.o: c_libs/%.cpp | |
| $(CXX) -Ofast -std=c++20 -c -shared -Wall -fPIC -I $(ERLANG_PATH) -fdiagnostics-color=always -o $@ $< |
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| defmodule Test.MixProject do | |
| use Mix.Project | |
| def project do | |
| [ | |
| app: :test, | |
| version: "0.1.0", | |
| elixir: "~> 1.13", | |
| start_permanent: Mix.env() == :prod, | |
| deps: deps(), | |
| compilers: [:elixir_make] ++ Mix.compilers(), | |
| releases: [ | |
| prod: [ | |
| strip_beams: false, | |
| config_providers: [ | |
| {TomlConfigProvider, path: {:system, "RELEASE_CONFIG_PATH"}}, | |
| ], | |
| ] | |
| ], | |
| ] | |
| end | |
| def application do | |
| [ | |
| mod: {Test.Main, []}, | |
| extra_applications: [:logger] | |
| ] | |
| end | |
| defp deps do | |
| [ | |
| {:elixir_make, "~> 0.4", runtime: false} | |
| ] | |
| end | |
| end |
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| #include <erl_nif.h> | |
| class MyPriv | |
| { | |
| ERL_NIF_TERM atom_ok_; | |
| public: | |
| MyPriv(ErlNifEnv* env): | |
| atom_ok_(enif_make_atom(env, "ok")) | |
| { | |
| } | |
| inline const auto& atom_ok() const | |
| { | |
| return this->atom_ok_; | |
| } | |
| }; | |
| ERL_NIF_TERM orders(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) noexcept | |
| { | |
| auto priv = reinterpret_cast<MyPriv*>(enif_priv_data(env)); | |
| return priv->atom_ok(); | |
| } | |
| static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info) noexcept | |
| { | |
| *priv_data = new MyPriv(env); | |
| return 0; | |
| } | |
| static int upgrade(ErlNifEnv* env, void** priv_data, void** old_priv_data, ERL_NIF_TERM load_info) noexcept | |
| { | |
| return load(env, priv_data, load_info); | |
| } | |
| static void unload(ErlNifEnv* env, void* priv_data) noexcept | |
| { | |
| delete reinterpret_cast<MyPriv*>(enif_priv_data(env)); | |
| } | |
| static ErlNifFunc nif_funcs[] = | |
| { | |
| {"orders", 0, orders} | |
| }; | |
| ERL_NIF_INIT(Elixir.Test.NativeProcessor.Lib, nif_funcs, load, NULL, upgrade, unload) |
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