Lately, my shell (zsh) feels slow to use. Even booting it for the first time feels like it is slow to render. It shouldn’t happen as I am using a beefy MacBook Pro. I also don’t don’t use any other zsh plugin other than git. So, I decided to investigate what is causing the slowness.
A quick search on the internet led me to the zsh profiling feature. I can profile the shell using this:
Put the following code at the start and end of your .zshrc file:
zmodload zsh/zprof
# your zshrc file content here.
zprof
Save it and source the ~/.zshrc file. Now, you can see the profiling output by running zprof.
num calls time self name
-----------------------------------------------------------------------------------
1) 1 3886.43 3886.43 93.04% 3348.16 3348.16 80.15% compinit
2) 831 381.00 0.46 9.12% 381.00 0.46 9.12% compdef
3) 2 169.68 84.84 4.06% 98.30 49.15 2.35% nvm
4) 1 86.15 86.15 2.06% 86.15 86.15 2.06% compdump
5) 2 71.57 35.78 1.71% 71.57 35.78 1.71% compaudit
6) 22 77.67 3.53 1.86% 58.00 2.64 1.39% _omz_source
7) 1 62.61 62.61 1.50% 54.07 54.07 1.29% nvm_ensure_version_installed
8) 1 209.63 209.63 5.02% 39.95 39.95 0.96% nvm_auto
9) 1 8.54 8.54 0.20% 8.54 8.54 0.20% nvm_is_version_installed
10) 1 8.33 8.33 0.20% 8.02 8.02 0.19% nvm_die_on_prefix
11) 1 6.24 6.24 0.15% 6.24 6.24 0.15% regexp-replace
12) 4 3.69 0.92 0.09% 3.69 0.92 0.09% add-zsh-hook
13) 1 3.62 3.62 0.09% 3.62 3.62 0.09% colors
14) 6 3.57 0.59 0.09% 3.57 0.59 0.09% is-at-least
15) 1 2.99 2.99 0.07% 2.99 2.99 0.07% zrecompile
16) 1 2.12 2.12 0.05% 2.12 2.12 0.05% test-ls-args
17) 1 0.44 0.44 0.01% 0.44 0.44 0.01% nvm_has
18) 2 0.31 0.16 0.01% 0.31 0.16 0.01% is_plugin
19) 4 0.31 0.08 0.01% 0.31 0.08 0.01% nvm_npmrc_bad_news_bears
20) 1 0.08 0.08 0.00% 0.04 0.04 0.00% complete
21) 3 0.04 0.01 0.00% 0.04 0.01 0.00% is_theme
22) 2 0.02 0.01 0.00% 0.02 0.01 0.00% bashcompinit
23) 2 0.02 0.01 0.00% 0.02 0.01 0.00% env_default
24) 1 209.65 209.65 5.02% 0.02 0.02 0.00% nvm_process_parameters
25) 1 0.01 0.01 0.00% 0.01 0.01 0.00% nvm_is_zsh
-----------------------------------------------------------------------------------
1) 1 3886.43 3886.43 93.04% 3348.16 3348.16 80.15% compinit
1/2 71.57 71.57 1.71% 0.28 0.28 compaudit [5]
1/1 86.15 86.15 2.06% 86.15 86.15 compdump [4]
818/831 380.55 0.47 9.11% 380.55 0.47 compdef [2]
-----------------------------------------------------------------------------------
818/831 380.55 0.47 9.11% 380.55 0.47 compinit [1]
12/831 0.41 0.03 0.01% 0.41 0.03 _omz_source [6]
1/831 0.04 0.04 0.00% 0.04 0.04 complete [20]
2) 831 381.00 0.46 9.12% 381.00 0.46 9.12% compdef
-----------------------------------------------------------------------------------
24) 1 209.65 209.65 5.02% 0.02 0.02 0.00% nvm_process_parameters
1/1 209.63 209.63 5.02% 39.95 39.95 nvm_auto [8]
-----------------------------------------------------------------------------------
1/1 209.63 209.63 5.02% 39.95 39.95 nvm_process_parameters [24]
8) 1 209.63 209.63 5.02% 39.95 39.95 0.96% nvm_auto
1/2 169.68 169.68 4.06% 4.92 4.92 nvm [3]
-----------------------------------------------------------------------------------
1/2 169.68 169.68 4.06% 4.92 4.92 nvm_auto [8]
1/2 164.76 164.76 3.94% 93.38 93.38 nvm [3]
3) 2 169.68 84.84 4.06% 98.30 49.15 2.35% nvm
1/1 0.44 0.44 0.01% 0.44 0.44 nvm_has [17]
1/1 8.33 8.33 0.20% 8.02 8.02 nvm_die_on_prefix [10]
1/1 62.61 62.61 1.50% 54.07 54.07 nvm_ensure_version_installed [7]
1/2 164.76 164.76 3.94% 93.38 93.38 nvm [3]
-----------------------------------------------------------------------------------
1/1 86.15 86.15 2.06% 86.15 86.15 compinit [1]
4) 1 86.15 86.15 2.06% 86.15 86.15 2.06% compdump
-----------------------------------------------------------------------------------
6) 22 77.67 3.53 1.86% 58.00 2.64 1.39% _omz_source
1/2 0.01 0.01 0.00% 0.01 0.01 bashcompinit [22]
2/2 0.02 0.01 0.00% 0.02 0.01 env_default [23]
12/831 0.41 0.03 0.01% 0.41 0.03 compdef [2]
1/1 2.12 2.12 0.05% 2.12 2.12 test-ls-args [16]
6/6 3.57 0.59 0.09% 3.57 0.59 is-at-least [14]
1/1 3.62 3.62 0.09% 3.62 3.62 colors [13]
4/4 3.69 0.92 0.09% 3.69 0.92 add-zsh-hook [12]
1/1 6.24 6.24 0.15% 6.24 6.24 regexp-replace [11]
-----------------------------------------------------------------------------------
1/2 71.57 71.57 1.71% 0.28 0.28 compinit [1]
1/2 71.29 71.29 1.71% 71.29 71.29 compaudit [5]
5) 2 71.57 35.78 1.71% 71.57 35.78 1.71% compaudit
1/2 71.29 71.29 1.71% 71.29 71.29 compaudit [5]
-----------------------------------------------------------------------------------
1/1 62.61 62.61 1.50% 54.07 54.07 nvm [3]
7) 1 62.61 62.61 1.50% 54.07 54.07 1.29% nvm_ensure_version_installed
1/1 8.54 8.54 0.20% 8.54 8.54 nvm_is_version_installed [9]
-----------------------------------------------------------------------------------
1/1 8.54 8.54 0.20% 8.54 8.54 nvm_ensure_version_installed [7]
9) 1 8.54 8.54 0.20% 8.54 8.54 0.20% nvm_is_version_installed
-----------------------------------------------------------------------------------
1/1 8.33 8.33 0.20% 8.02 8.02 nvm [3]
10) 1 8.33 8.33 0.20% 8.02 8.02 0.19% nvm_die_on_prefix
4/4 0.31 0.08 0.01% 0.31 0.08 nvm_npmrc_bad_news_bears [19]
-----------------------------------------------------------------------------------
1/1 6.24 6.24 0.15% 6.24 6.24 _omz_source [6]
11) 1 6.24 6.24 0.15% 6.24 6.24 0.15% regexp-replace
-----------------------------------------------------------------------------------
4/4 3.69 0.92 0.09% 3.69 0.92 _omz_source [6]
12) 4 3.69 0.92 0.09% 3.69 0.92 0.09% add-zsh-hook
-----------------------------------------------------------------------------------
1/1 3.62 3.62 0.09% 3.62 3.62 _omz_source [6]
13) 1 3.62 3.62 0.09% 3.62 3.62 0.09% colors
-----------------------------------------------------------------------------------
6/6 3.57 0.59 0.09% 3.57 0.59 _omz_source [6]
14) 6 3.57 0.59 0.09% 3.57 0.59 0.09% is-at-least
-----------------------------------------------------------------------------------
15) 1 2.99 2.99 0.07% 2.99 2.99 0.07% zrecompile
-----------------------------------------------------------------------------------
1/1 2.12 2.12 0.05% 2.12 2.12 _omz_source [6]
16) 1 2.12 2.12 0.05% 2.12 2.12 0.05% test-ls-args
-----------------------------------------------------------------------------------
1/1 0.44 0.44 0.01% 0.44 0.44 nvm [3]
17) 1 0.44 0.44 0.01% 0.44 0.44 0.01% nvm_has
-----------------------------------------------------------------------------------
18) 2 0.31 0.16 0.01% 0.31 0.16 0.01% is_plugin
-----------------------------------------------------------------------------------
4/4 0.31 0.08 0.01% 0.31 0.08 nvm_die_on_prefix [10]
19) 4 0.31 0.08 0.01% 0.31 0.08 0.01% nvm_npmrc_bad_news_bears
-----------------------------------------------------------------------------------
20) 1 0.08 0.08 0.00% 0.04 0.04 0.00% complete
1/831 0.04 0.04 0.00% 0.04 0.04 compdef [2]
-----------------------------------------------------------------------------------
21) 3 0.04 0.01 0.00% 0.04 0.01 0.00% is_theme
-----------------------------------------------------------------------------------
1/2 0.01 0.01 0.00% 0.01 0.01 _omz_source [6]
22) 2 0.02 0.01 0.00% 0.02 0.01 0.00% bashcompinit
-----------------------------------------------------------------------------------
2/2 0.02 0.01 0.00% 0.02 0.01 _omz_source [6]
23) 2 0.02 0.01 0.00% 0.02 0.01 0.00% env_default
-----------------------------------------------------------------------------------
25) 1 0.01 0.01 0.00% 0.01 0.01 0.00% nvm_is_zsh
If notice the output you would see the nvm showing prominently in it. It means it’s the reason for the slowness.
Here is my ~/.zshrc file for reference:
# If you come from bash you might have to change your $PATH.
# export PATH=$HOME/bin:/usr/local/bin:$PATH
# Path to your oh-my-zsh installation.
export ZSH="$HOME/.oh-my-zsh"
# Set name of the theme to load --- if set to "random", it will
# load a random theme each time oh-my-zsh is loaded, in which case,
# to know which specific one was loaded, run: echo $RANDOM_THEME
# See https://github.com/ohmyzsh/ohmyzsh/wiki/Themes
ZSH_THEME="robbyrussell"
# Set list of themes to pick from when loading at random
# Setting this variable when ZSH_THEME=random will cause zsh to load
# a theme from this variable instead of looking in $ZSH/themes/
# If set to an empty array, this variable will have no effect.
# ZSH_THEME_RANDOM_CANDIDATES=( "robbyrussell" "agnoster" )
# 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 one of the following lines to change the auto-update behavior
# zstyle ':omz:update' mode disabled # disable automatic updates
# zstyle ':omz:update' mode auto # update automatically without asking
# zstyle ':omz:update' mode reminder # just remind me to update when it's time
# Uncomment the following line to change how often to auto-update (in days).
# zstyle ':omz:update' frequency 13
# Uncomment the following line if pasting URLs and other text is messed up.
# DISABLE_MAGIC_FUNCTIONS="true"
# 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.
# You can also set it to another string to have that shown instead of the default red dots.
# e.g. COMPLETION_WAITING_DOTS="%F{yellow}waiting...%f"
# Caution: this setting can cause issues with multiline prompts in zsh < 5.7.1 (see #5765)
# 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.
# You can set one of the optional three formats:
# "mm/dd/yyyy"|"dd.mm.yyyy"|"yyyy-mm-dd"
# or set a custom format using the strftime function format specifications,
# see 'man strftime' for details.
# 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?
# Standard plugins can be found in $ZSH/plugins/
# Custom plugins may be added to $ZSH_CUSTOM/plugins/
# Example format: plugins=(rails git textmate ruby lighthouse)
# Add wisely, as too many plugins slow down shell startup.
plugins=(git)
alias c='clear'
alias activate='source venv/bin/activate'
alias syncall='gco develop && ggpull && gco staging && ggpull && gco master && ggpull'
alias vim="nvim"
alias vi="nvim"
alias v="nvim"
source $ZSH/oh-my-zsh.sh
# User configuration
# export MANPATH="/usr/local/man:$MANPATH"
# You may need to manually set your language environment
# export LANG=en_US.UTF-8
# Preferred editor for local and remote sessions
if [[ -n $SSH_CONNECTION ]]; then
export EDITOR='vim'
else
export EDITOR='mvim'
fi
# Compilation flags
# export ARCHFLAGS="-arch x86_64"
# Set personal aliases, overriding those provided by oh-my-zsh libs,
# plugins, and themes. Aliases can be placed here, though oh-my-zsh
# users are encouraged to define aliases within the ZSH_CUSTOM folder.
# For a full list of active aliases, run `alias`.
#
# Example aliases
# alias zshconfig="mate ~/.zshrc"
# alias ohmyzsh="mate ~/.oh-my-zsh"
eval "$(zoxide init zsh)"
. "$HOME/.cargo/env"
export PATH="/opt/homebrew/opt/ruby/bin:$PATH"
[ -f ~/.fzf.zsh ] && source ~/.fzf.zsh
# export NVM_DIR="$HOME/.nvm"
# [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" # This loads nvm
# [ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion" # This loads nvm bash_completion
Now, NVM is an useful tool, but it doesn’t need to be enabled all the time for my day to day development. So, I decided to just comment nvm for now and uncomment it as and when needed.
~Fin
Finally, my shell is back to normal speed. I hope this helps you too.