How to improve load time of zsh in babun on windows?

Question

I love ZSH shell and its themes but it is very slow. It takes 7 to 10 seconds to load. I also use it as a integrated terminal in VS Code even though it's slow to load. Here is a copy of my .zshrc file.

# Path to your oh-my-zsh installation.
export ZSH=$HOME/.oh-my-zsh
export PS1="[%* - %D] %d %% "


# Set name of the theme to load. 
# Look in ~/.oh-my-zsh/themes/
# Optionally, if you set this to "random", it'll load a random theme each
# time that oh-my-zsh is loaded.
ZSH_THEME="agnoster"
DEFAULT_USER=13000

# Uncomment the following line to use case-sensitive completion.
# CASE_SENSITIVE="true"

# Uncomment the following line to use hyphen-insensitive completion. Case
# sensitive completion must be off. _ and - will be interchangeable.
# HYPHEN_INSENSITIVE="true"

# Uncomment the following line to disable bi-weekly auto-update checks.
# DISABLE_AUTO_UPDATE="true"

# Uncomment the following line to change how often to auto-update (in days).
# export UPDATE_ZSH_DAYS=13

# Uncomment the following line to disable colors in ls.
# DISABLE_LS_COLORS="true"

# Uncomment the following line to disable auto-setting terminal title.
# DISABLE_AUTO_TITLE="true"

# Uncomment the following line to enable command auto-correction.
# ENABLE_CORRECTION="true"

# Uncomment the following line to display red dots whilst waiting for 
  completion.
# COMPLETION_WAITING_DOTS="true"

# Uncomment the following line if you want to disable marking untracked 
  files
# under VCS as dirty. This makes repository status check for large 
  repositories
# much, much faster.
# DISABLE_UNTRACKED_FILES_DIRTY="true"

# Uncomment the following line if you want to change the command execution 
  time
# stamp shown in the history command output.
# The optional three formats: "mm/dd/yyyy"|"dd.mm.yyyy"|"yyyy-mm-dd"
# HIST_STAMPS="mm/dd/yyyy"

# Would you like to use another custom folder than $ZSH/custom?
# ZSH_CUSTOM=/path/to/new-custom-folder

# Which plugins would you like to load? (plugins can be found in ~/.oh-my-
  zsh/plugins/*)
# Custom plugins may be added to ~/.oh-my-zsh/custom/plugins/
# Example format: plugins=(rails git textmate ruby lighthouse)
# Add wisely, as too many plugins slow down shell startup.
  plugins=(git)

# User configuration

export PATH=$HOME/bin:/usr/local/bin:$PATH
# export MANPATH="/usr/local/man:$MANPATH"

source $ZSH/oh-my-zsh.sh


# You may need to manually set your language environment
# export LANG=en_US.UTF-8

# Preferred editor for local and remote sessions
# if [[ -n $SSH_CONNECTION ]]; then
#   export EDITOR='vim'
# else
#   export EDITOR='mvim'
# fi

# Compilation flags
# export ARCHFLAGS="-arch x86_64"

# ssh
# export SSH_KEY_PATH="~/.ssh/dsa_id"

# Set personal aliases, overriding those provided by oh-my-zsh libs,
# plugins, and themes. Aliases can be placed here, though oh-my-zsh
# users are encouraged to define aliases within the ZSH_CUSTOM folder.
# For a full list of active aliases, run `alias`.
#
# Example aliases
# alias zshconfig="mate ~/.zshrc"
# alias ohmyzsh="mate ~/.oh-my-zsh"

prompt_dir() {
  prompt_segment blue black "${PWD##*/}"
}

EDIT :: I found 2 oh-my-zsh.sh file in my cygwin directory so here are the both of them.

First one

# Check for updates on initial load...
if [ "$DISABLE_AUTO_UPDATE" != "true" ]; then
  env ZSH=$ZSH DISABLE_UPDATE_PROMPT=$DISABLE_UPDATE_PROMPT zsh -f 
$ZSH/tools/check_for_upgrade.sh
fi

# Initializes Oh My Zsh

# add a function path
fpath=($ZSH/functions $ZSH/completions $fpath)

# Load all stock functions (from $fpath files) called below.
autoload -U compaudit compinit

: ${ZSH_DISABLE_COMPFIX:=true}

# Set ZSH_CUSTOM to the path where your custom config files
# and plugins exists, or else we will use the default custom/
if [[ -z "$ZSH_CUSTOM" ]]; then
    ZSH_CUSTOM="$ZSH/custom"
fi

# Set ZSH_CACHE_DIR to the path where cache files should be created
# or else we will use the default cache/
if [[ -z "$ZSH_CACHE_DIR" ]]; then
  ZSH_CACHE_DIR="$ZSH/cache"
fi


# Load all of the config files in ~/oh-my-zsh that end in .zsh
# TIP: Add files you don't want in git to .gitignore
for config_file ($ZSH/lib/*.zsh); do
  custom_config_file="${ZSH_CUSTOM}/lib/${config_file:t}"
  [ -f "${custom_config_file}" ] && config_file=${custom_config_file}
  source $config_file
done


is_plugin() {
  local base_dir=$1
  local name=$2
  test -f $base_dir/plugins/$name/$name.plugin.zsh \
    || test -f $base_dir/plugins/$name/_$name
}
# Add all defined plugins to fpath. This must be done
# before running compinit.
for plugin ($plugins); do
  if is_plugin $ZSH_CUSTOM $plugin; then
fpath=($ZSH_CUSTOM/plugins/$plugin $fpath)
  elif is_plugin $ZSH $plugin; then
    fpath=($ZSH/plugins/$plugin $fpath)
  fi
done

# Figure out the SHORT hostname
if [[ "$OSTYPE" = darwin* ]]; then
  # macOS's $HOST changes with dhcp, etc. Use ComputerName if possible.
  SHORT_HOST=$(scutil --get ComputerName 2>/dev/null) || 
SHORT_HOST=${HOST/.*/}
else
  SHORT_HOST=${HOST/.*/}
fi

# Save the location of the current completion dump file.
if [ -z "$ZSH_COMPDUMP" ]; then
  ZSH_COMPDUMP="${ZDOTDIR:-${HOME}}/.zcompdump-${SHORT_HOST}-${ZSH_VERSION}"
fi

if [[ $ZSH_DISABLE_COMPFIX != true ]]; then
  # If completion insecurities exist, warn the user without enabling 
completions.
  if ! compaudit &>/dev/null; then
    # This function resides in the "lib/compfix.zsh" script sourced above.
    handle_completion_insecurities
  # Else, enable and cache completions to the desired file.
  else
    compinit -d "${ZSH_COMPDUMP}"
  fi
else
  compinit -i -d "${ZSH_COMPDUMP}"
fi

# Load all of the plugins that were defined in ~/.zshrc
for plugin ($plugins); do
  if [ -f $ZSH_CUSTOM/plugins/$plugin/$plugin.plugin.zsh ]; then
    source $ZSH_CUSTOM/plugins/$plugin/$plugin.plugin.zsh
  elif [ -f $ZSH/plugins/$plugin/$plugin.plugin.zsh ]; then
    source $ZSH/plugins/$plugin/$plugin.plugin.zsh
  fi
done

# Load all of your custom configurations from custom/
for config_file ($ZSH_CUSTOM/*.zsh(N)); do
  source $config_file
done
unset config_file

# Load the theme
if [ "$ZSH_THEME" = "random" ]; then
  themes=($ZSH/themes/*zsh-theme)
  N=${#themes[@]}
  ((N=(RANDOM%N)+1))
  RANDOM_THEME=${themes[$N]}
  source "$RANDOM_THEME"
  echo "[oh-my-zsh] Random theme '$RANDOM_THEME' loaded..."
else
  if [ ! "$ZSH_THEME" = ""  ]; then
    if [ -f "$ZSH_CUSTOM/$ZSH_THEME.zsh-theme" ]; then
      source "$ZSH_CUSTOM/$ZSH_THEME.zsh-theme"
    elif [ -f "$ZSH_CUSTOM/themes/$ZSH_THEME.zsh-theme" ]; then
      source "$ZSH_CUSTOM/themes/$ZSH_THEME.zsh-theme"
    else
      source "$ZSH/themes/$ZSH_THEME.zsh-theme"
    fi
  fi
fi

The second one is

# Check for updates on initial load...
if [ "$DISABLE_AUTO_UPDATE" != "true" ]; then
  env ZSH=$ZSH DISABLE_UPDATE_PROMPT=$DISABLE_UPDATE_PROMPT zsh -f 
$ZSH/tools/check_for_upgrade.sh
fi

# Initializes Oh My Zsh

# add a function path
fpath=($ZSH/functions $ZSH/completions $fpath)

# Set ZSH_CUSTOM to the path where your custom config files
# and plugins exists, or else we will use the default custom/
if [[ -z "$ZSH_CUSTOM" ]]; then
    ZSH_CUSTOM="$ZSH/custom"
fi

# Set ZSH_CACHE_DIR to the path where cache files should be created
# or else we will use the default cache/
if [[ -z "$ZSH_CACHE_DIR" ]]; then
  ZSH_CACHE_DIR="$ZSH/cache/"
fi


# Load all of the config files in ~/oh-my-zsh that end in .zsh
# TIP: Add files you don't want in git to .gitignore
for config_file ($ZSH/lib/*.zsh); do
  custom_config_file="${ZSH_CUSTOM}/lib/${config_file:t}"
  [ -f "${custom_config_file}" ] && config_file=${custom_config_file}
  source $config_file
done

# Load all of your custom configurations from custom/
for config_file ($ZSH_CUSTOM/*.zsh(N)); do
  source $config_file
done
unset config_file

is_plugin() {
  local base_dir=$1
  local name=$2
  test -f $base_dir/plugins/$name/$name.plugin.zsh \
    || test -f $base_dir/plugins/$name/_$name
}
# Add all defined plugins to fpath. This must be done
# before running compinit.
for plugin ($plugins); do
  if is_plugin $ZSH_CUSTOM $plugin; then
    fpath=($ZSH_CUSTOM/plugins/$plugin $fpath)
  elif is_plugin $ZSH $plugin; then
    fpath=($ZSH/plugins/$plugin $fpath)
  fi
done

# Figure out the SHORT hostname
if [[ "$OSTYPE" = darwin* ]]; then
  # OS X's $HOST changes with dhcp, etc. Use ComputerName if possible.
  SHORT_HOST=$(scutil --get ComputerName 2>/dev/null) || 
SHORT_HOST=${HOST/.*/}
else
  SHORT_HOST=${HOST/.*/}
fi

# Save the location of the current completion dump file.
if [ -z "$ZSH_COMPDUMP" ]; then
  ZSH_COMPDUMP="${ZDOTDIR:-${HOME}}/.zcompdump-${SHORT_HOST}-${ZSH_VERSION}"
fi

# Load and run compinit
autoload -U compinit
compinit -i -d "${ZSH_COMPDUMP}"

# Load all of the plugins that were defined in ~/.zshrc
for plugin ($plugins); do
  if [ -f $ZSH_CUSTOM/plugins/$plugin/$plugin.plugin.zsh ]; then
    source $ZSH_CUSTOM/plugins/$plugin/$plugin.plugin.zsh
  elif [ -f $ZSH/plugins/$plugin/$plugin.plugin.zsh ]; then
    source $ZSH/plugins/$plugin/$plugin.plugin.zsh
  fi
done

# Load the theme
if [ "$ZSH_THEME" = "random" ]; then
  themes=($ZSH/themes/*zsh-theme)
  N=${#themes[@]}
  ((N=(RANDOM%N)+1))
  RANDOM_THEME=${themes[$N]}
  source "$RANDOM_THEME"
  echo "[oh-my-zsh] Random theme '$RANDOM_THEME' loaded..."
else
  if [ ! "$ZSH_THEME" = ""  ]; then
    if [ -f "$ZSH_CUSTOM/$ZSH_THEME.zsh-theme" ]; then
      source "$ZSH_CUSTOM/$ZSH_THEME.zsh-theme"
    elif [ -f "$ZSH_CUSTOM/themes/$ZSH_THEME.zsh-theme" ]; then
      source "$ZSH_CUSTOM/themes/$ZSH_THEME.zsh-theme"
    else
      source "$ZSH/themes/$ZSH_THEME.zsh-theme"
    fi
  fi
fi

Do not mind the long post :D.

Answer 1

I've installed babun on my Windows 10 machine.

Disabling bash autocompletion jobs slightly improved my loading time. I renamed all my files to ".bk" extensions in the "bash_completion.d" directory.

{ ~ }  » ls -ltr /etc/bash_completion.d                                                         ~
total 68
-rwxrwx---+ 1 m.ortiz.montealegre Domain Users   998 Jun 23  2015 vim-completion.bk
-rwxrwx---+ 1 m.ortiz.montealegre Domain Users 44924 Jun 23  2015 svn.bk
-rwxrwx---+ 1 m.ortiz.montealegre Domain Users  1200 Jun 23  2015 gvim-completion.bk
-rwxrwx---+ 1 m.ortiz.montealegre Domain Users  2609 Jun 23  2015 gsettings.bk
-rwxrwx---+ 1 m.ortiz.montealegre Domain Users  1356 Jun 23  2015 gresource.bk
-rwxrwx---+ 1 m.ortiz.montealegre Domain Users   935 Jun 23  2015 gdbus.bk
-rwxrwx---+ 1 m.ortiz.montealegre Domain Users  1389 Jun 23  2015 gapplication.bk

Also debugging is a good option with strace to see what's going on while Cygwin is loading, please check this question.

EDIT:

About Babun tweaking

A tool you could use to check your installation is documented in the babun website, use babun check maybe this offer you some clue:

{ ~ } » babun check                                                                          ~
Executing babun check
Prompt speed      [SLOW]
Hint: your prompt is very slow. Check the installed 'BLODA' software.
Connection check  [OK]
Update check      [OK]
Cygwin check      [OK]

I don't know if you performed some tweaking in your babun installation, please check your ~/.babunrc file and verify you've disabled auto-updates and startup checks (do not enable them):

# JVM options
export JAVA_OPTS="-Xms128m -Xmx256m"

# Modify these lines to set your locale
export LANG="en_US.UTF-8"
export LC_CTYPE="en_US.UTF-8"
export LC_ALL="en_US.UTF-8"

# Uncomment these lines to the set your machine's default locale (and comment out the UTF-8 ones)
# export LANG=$(locale -uU)
# export LC_CTYPE=$(locale -uU)
# export LC_ALL=$(locale -uU)

# Uncomment this to disable daily auto-update & proxy checks on startup (not recommended!)
# export DISABLE_CHECK_ON_STARTUP="true"

# Uncomment to increase/decrease the check connection timeout
# export CHECK_TIMEOUT_IN_SECS=4

# Uncomment this lines to set up your proxy
# export http_proxy=http://user:password@server:port
# export https_proxy=$http_proxy
# export ftp_proxy=$http_proxy
# export no_proxy=localhost

About Cygwin

There are several tweaks here and here you could explore for Cygwin if you aren't happy debugging with Strace.

I think you should abstract the "babun" thing and don't forget about the embeded Cygwin which I think is what you really what to speed up, the babun core is a Cygwin implementation with some changes:

The core of Babun consists of a pre-configured Cygwin.