Vim configuration slow in Terminal & iTerm2 but not in MacVim

Ideally, I want to use Vim from Terminal or iTerm2. However, it becomes unbearably slow so I had to resort to using MacVim. There is nothing wrong with MacVim, however my workflow would be much smoother if I used only Terminal/iTerm2.

When its slow

• Loading files, in particular Rails files takes about 1 - 1.5s. Removing rails.vim decreases this time to 0.5 - 1s. In MacVim this is instantaneous.

• Scrolling through the rows and columns via h, j, k, l. It progressively gets slower the longer I hold down the keys. Eventually, it starts jumping rows. I have my Key Repeat set to Fast and Delay Until Repeat set to Short.

• After 10 - 15 minutes of usage, using plugins such as ctrlp or Command-T gets very laggy. I'd type a letter, wait 2 - 3s, then type the next.

My Setup

11" MacBook Air running Mac OS X Version 10.7.3 (1.6 Ghz Intel Core 2 Duo, 4 GB DDR3)

My dotfiles.

> vim --version
VIM - Vi IMproved 7.3 (2010 Aug 15, compiled Nov 16 2011 16:44:23)
MacOS X (unix) version
Included patches: 1-333
Huge version without GUI.  Features included (+) or not (-):
+arabic +autocmd -balloon_eval -browse ++builtin_terms +byte_offset +cindent 
-clientserver +clipboard +cmdline_compl +cmdline_hist +cmdline_info +comments 
+conceal +cryptv -cscope +cursorbind +cursorshape +dialog_con +diff +digraphs 
-dnd -ebcdic +emacs_tags +eval +ex_extra +extra_search +farsi +file_in_path 
+find_in_path +float +folding -footer +fork() -gettext -hangul_input +iconv 
+insert_expand +jumplist +keymap +langmap +libcall +linebreak +lispindent 
+listcmds +localmap -lua +menu +mksession +modify_fname +mouse -mouseshape 
+mouse_dec -mouse_gpm -mouse_jsbterm +mouse_netterm -mouse_sysmouse 
+mouse_xterm +multi_byte +multi_lang -mzscheme +netbeans_intg +path_extra -perl
 +persistent_undo +postscript +printer +profile +python -python3 +quickfix 
+reltime +rightleft +ruby +scrollbind +signs +smartindent -sniff +startuptime 
+statusline -sun_workshop +syntax +tag_binary +tag_old_static -tag_any_white 
-tcl +terminfo +termresponse +textobjects +title -toolbar +user_commands 
+vertsplit +virtualedit +visual +visualextra +viminfo +vreplace +wildignore 
+wildmenu +windows +writebackup -X11 -xfontset -xim -xsmp -xterm_clipboard 
-xterm_save 
   system vimrc file: "$VIM/vimrc"
     user vimrc file: "$HOME/.vimrc"
      user exrc file: "$HOME/.exrc"
  fall-back for $VIM: "/usr/local/Cellar/vim/7.3.333/share/vim"
Compilation: /usr/bin/llvm-gcc -c -I. -Iproto -DHAVE_CONFIG_H   -DMACOS_X_UNIX -no-cpp-precomp  -O3 -march=core2 -msse4.1 -w -pipe -D_FORTIFY_SOURCE=1      
Linking: /usr/bin/llvm-gcc   -L.     -L/usr/local/lib -o vim       -lm  -lncurses -liconv -framework Cocoa     -framework Python   -lruby

I've tried running without any plugins or syntax highlighting. It opens files a lot faster but still not as fast as MacVim. But the other two problems still exist.

1. Why is my vim configuration slow?
2. How can I improve the speed of my vim configuration within Terminal or iTerm2?

Solution 1:

I've tried a good dozen times to compile Vim on my Mac but I've never managed to obtain a usable Vim: each time it worked but it was unbearably slow and laggy.

After loosing too much time trying to make it work I simply dropped the towel and created an alias to MacVim's bundled CLI executable.

alias vim='/path/to/MacVim.app/Content/MacOS/Vim'

Not only is it fast and responsive but it has the exact same features you could find in MacVim, as long as it makes sense in a terminal. Since then, using MacVim and/or Vim makes no difference for me and whether I use one or the other is dictated only by the context. Not by one being better than the other.

Why is my vim configuration slow? How can I improve the speed of my vim configuration within Terminal or iTerm2?

By using MacVim's pre-compiled binary.

Also try Linux one day. MacVim is fast only if you have never used GVim or Vim on a linux box.

Solution 2:

I've found that any plugins or settings that affect the display (cursorline, cursorcolumn, vim-powerline, vim-airline, matchit.vim, etc.) slow down Vim in the terminal most significantly.

Here are some lines from my .vimrc to keep things speedy:

let loaded_matchparen=1 " Don't load matchit.vim (paren/bracket matching)
set noshowmatch         " Don't match parentheses/brackets
set nocursorline        " Don't paint cursor line
set nocursorcolumn      " Don't paint cursor column
set lazyredraw          " Wait to redraw
set scrolljump=8        " Scroll 8 lines at a time at bottom/top
let html_no_rendering=1 " Don't render italic, bold, links in HTML

Also see :help slow-terminal

That said, why Vim in the terminal is slower is beyond me.