t-vim: A tale of two editors

Posted on April 29, 2020

Since I am looking at merging a few pull requests for t-vim, I thought that this will also be a good time to implement a simple feature that was on hold for a while: the ability to use the module with Neovim instead of vim.

Neovim is the new kid on the block, with the tag line of Rebuilding Vim for the 21st century. Neovim modernizes the vim codebase with the objective of making it easier to write plugins and customizations at the cost of removing support for old platforms and esoteric features of Vim. I will not go into the political debate of which philosophy is better.

For the most part, neovim is backward compatible with vim. So, in principle, it should be straight forward to use neovim as a backend for t-vim. I just released a new version of t-vim, which makes this possible.


As a side effect, it is now also possible to call the module if vim (or nvim) are not in $PATH.


Speed tests

So, how do vim and neovim compare in running 2context.vim. I did a few tests and it turns out that the startup time of both of them are similar, but nvim is 7-10% faster in processing 2context.vim for medium sized files. For example, with a 500 line matlab file, this is the amount of time for vim to process the file:

times in msec
 clock   self+sourced   self:  sourced script
 clock   elapsed:              other lines

000.007  000.007: --- VIM STARTING ---
000.141  000.134: Allocated generic buffers
000.239  000.098: locale set
000.269  000.030: GUI prepared
000.274  000.005: clipboard setup
000.280  000.006: window checked
000.777  000.497: inits 1
000.910  000.133: parsing arguments
000.912  000.002: expanding arguments
000.950  000.038: shell init
001.005  000.055: inits 2
001.229  000.224: init highlight
001.231  000.002: sourcing vimrc file(s)
001.252  000.021: inits 3
001.254  000.002: setup clipboard
001.256  000.002: setting raw mode
001.256  000.000: start termcap
001.787  000.531: opening buffers
001.789  000.002: BufEnter autocommands
001.790  000.001: editing files in windows
003.192  001.173  001.173: sourcing /usr/share/vim/vim82/syntax/syncolor.vim
003.362  001.441  000.268: sourcing /usr/share/vim/vim82/syntax/synload.vim
003.408  001.563  000.122: sourcing /usr/share/vim/vim82/syntax/manual.vim
013.617  010.022  010.022: sourcing /usr/share/vim/vim82/syntax/matlab.vim
1184.729  1170.948  1170.948: sourcing /opt/luametatex/texmf-modules/tex/context/third/vim/2context.vim

Note that most of the time (1.17 sec out of 1.18 sec) is spent in processing the 2context.vim script. Starting up vim until that point just takes 0.13 sec). Now, let’s check nvim:

times in msec
 clock   self+sourced   self:  sourced script
 clock   elapsed:              other lines

000.010  000.010: --- NVIM STARTING ---
000.453  000.442: locale set
000.832  000.380: inits 1
000.855  000.022: window checked
000.949  000.094: parsing arguments
001.011  000.063: expanding arguments
001.017  000.006: inits 2
001.855  000.837: init highlight
001.977  000.123: sourcing vimrc file(s)
001.999  000.022: inits 3
002.001  000.002: reading ShaDa
002.480  000.479: opening buffers
002.483  000.004: BufEnter autocommands
002.485  000.002: editing files in windows
003.040  000.338  000.338: sourcing /usr/share/nvim/runtime/syntax/syncolor.vim
003.192  000.590  000.252: sourcing /usr/share/nvim/runtime/syntax/synload.vim
003.229  000.693  000.103: sourcing /usr/share/nvim/runtime/syntax/manual.vim
003.784  000.379  000.379: sourcing /usr/share/nvim/runtime/syntax/matlab.vim
1014.988  1011.055  1011.055: sourcing /opt/luametatex/texmf-modules/tex/context/third/vim/2context.vim

The initialization and loading of files until manual.vim takes roughly the same time for both vim and neovim1, but then neovim is significantly faster in loading mathlab.vim and slightly faster in loading 2context.vim. Overall, this leads to a gain of about 8-10%. For bigger files (a 2000 line context file), nvim is 13% faster. Thus, using nvim as a backend has negligible effect for short files but significantly speeds up performance for medium and larger files. I am going to be using it as a default for my setup from now!

  1. A notable exception is init highlight where nvim is about 4 times slower than vim! [return]

This entry was posted in T-Vim and tagged efficiency.