tony612

package main

import (
	"bytes"
	"crypto"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/x509"
	"crypto/x509/pkix"

tony612

package main

// Run this in root of https://github.com/vscode-kubernetes-tools/vscode-kubernetes-tools
// `snippets` dir is used.
// Somehow vscode can't show snippets by default.

import (
	"encoding/json"
	"fmt"
	"io/fs"

tony612

package main

import (
	"crypto/tls"
	"crypto/x509"
	"flag"
	"io"
	"io/ioutil"
	"log"
	"os"

tony612

export USERNAME=myadmin
export GROUPNAME=myadmin
export CERTIFICATE_NAME=myadmin
openssl genrsa -out ${USERNAME}.key 2048

openssl req -new -key ${USERNAME}.key -out ${USERNAME}.csr -subj "/CN=${USERNAME}/O=${GROUPNAME}"

cat <<EOF | kubectl apply -f -
apiVersion: certificates.k8s.io/v1beta1
kind: CertificateSigningRequest

tony612

Erlang honors cgroup CPU quota from Erlang 23. But when less than 1 CPU is used, schedulers_online will be cores number(see below k8s 0-5).

docker

$ docker run --rm -it --cpu-period 100000 --cpu-quota 100000 erlang:23 bash
root@3f793576001a:/# erl
Erlang/OTP 23 [erts-11.0.2] [source] [64-bit] [smp:4:1] [ds:4:1:10] [async-threads:1] [hipe]

tony612

def read_until_eof():
  buffer = ''
  batch_size = 1024
  while True:
    ready, _, _ = select.select([sys.stdin], [], [], 0.0)
    if sys.stdin not in ready:
      continue

    # Don't know why, but sys.stdin.read() and sys.stdin.readline()
    # will cause EPIPE when writting to stdout

tony612

#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>

int main(void) {
  size_t pagesize = getpagesize();

  printf("System page size: %zu bytes\n", pagesize);

tony612

defmodule BinaryParseSlow do
  def parse(bin) do
    parse(bin, 0)
  end

  def parse(bin, acc) do
    case do_parse(bin) do
      {:nofin, x, rest} ->
        parse(rest, acc + x)
      {:fin, x} ->

tony612

# For binary 0000 0001 0100 0000 1000 1000
# The result is 0b1 + 0b100_0000 + 0b1000 = 73
defmodule BinaryParseFast do
  def parse(bin) do
    parse(bin, 0)
  end

  # A byte beginning with 0 means the end, but still need to add the last 7 bits
  def parse(<<0::1, x::7, _::bits>>, acc), do: acc + x
  # A byte beginning with 1 means there is more data needed to be processed.

tony612

for a1 <- 0..1,
      a2 <- 0..1,
      a3 <- 0..1,
      a4 <- 0..1,
      a5 <- 0..1,
      a6 <- 0..1,
      a7 <- 0..1,
      a8 <- 0..1,
      a9 <- 0..1,