Zabrane

MiniPerf

Example of how to capture CPU counters with ETW on Windows, perf on Linux or kperf on Apple.

Using ETW needs somewhat recently updated Windows 10 or 11. Not sure about exact version.

Currently tested on:

etw on Qualcomm Snapdragon X Elite, Windows 11, arm64
etw on AMD Zen 3, Windows 11 (with virtualization enabled in BIOS)

enable https on your local environment

install mkcert and create certificates

brew install mkcert

mkcert -install

How to Create a Cowboy Middleware

Add an entry to the middlewares. Usually you want to keep the standard Cowboy handlers afterwards, but you can replace them if you want.

{ok, Pid} = cowboy:start_clear(ListenerName,
    [{port, Port}],
    #{
 env =&gt; #{dispatch =&gt; Dispatch},

How to Create a Cowboy Stream Handler

Add your stream handler to the list of stream handlers in the protocol options:

{ok, Pid} = cowboy:start_clear(ListenerName,
    [{port, Port}],
    #{
        env => #{dispatch => Dispatch},
 stream_handlers =&gt; [my_stream_h, cowboy_compress_h, cowboy_stream_h]

Cowboy, the popular Erlang web server, has deprecated middleware and replaced the concept with stream handlers, a more flexible, but more complicated API. This page contains a documented reference implementation of a stream handler, to help others when developing their stream handlers in the future.

	// Examples of quick hash tables and dynamic arrays in C
	// https://nullprogram.com/blog/2025/01/19/
	// This is free and unencumbered software released into the public domain.
	#include <assert.h>
	#include <stdarg.h>
	#include <stddef.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	; -------------------------------------------------------------------
	; Sna86.
	; An 8086 simulator snake!
	; -------------------------------------------------------------------
	;
	; Assembly program intended to run in an 8086 simulator with functionaliy equal* to one made for homeworks
	; up to Part 1 Episode 10 of the Peformance-Aware Programming Series (https://www.computerenhance.com/)
	; by Casey Muratori. Demo - https://youtu.be/s_S4-QHeFMc.
	;
	; * mov, add, sub, cmp, je and jne was the target instructions. However I also added loop for convenience,

	-module(otel).
	-include_lib("kernel/include/logger.hrl").
	-include_lib("corelib/include/corelib_openapi.hrl").

	-export([start_trace/0, start_trace/1]).
	-export([end_trace/0]).
	-export([start_span/0, start_span/1]).
	-export([end_span/0, end_span/1]).
	-export([setattrs/1, setname/1]).
	-export([get_context/0, set_context/1]).

	###############################################################################
	# Use:
	# - docker build --progress plain --tag docker.io/containercraft/pandoc -f Dockerfile .
	# - docker run --rm -it --name pandoc --hostname pandoc --volume .:/convert docker.io/containercraft/pandoc my_document.md

	###############################################################################
	FROM docker.io/library/ubuntu:24.04
	LABEL tag="pandoc"
	ENV DEVCONTAINER="pandoc"
	SHELL ["/bin/bash", "-c", "-e"]

	#include <sys/mman.h>
	#include <sys/stat.h>
	#include <erl_nif.h>
	#include <unistd.h>
	#include <stdint.h>
	#include <string.h>
	#include <fcntl.h>


	static ErlNifResourceType* shmem_resource;