I'm using Vim primarily for rails projects, and have found a fairly significant difference in the start up time between a couple of my projects.
Here's one project's startuptime log, while opening a single .rb file:
185.767 002.679 002.679: sourcing /usr/share/vim/vim81/syntax/ruby.vim
190.811 004.781 004.781: sourcing /home/thomas/.vim/bundle/vim-rails/autoload/rails.vim
478.080 000.275 000.275: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions.vim
478.257 000.061 000.061: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/quickfix.vim
478.484 000.156 000.156: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline.vim
478.645 000.035 000.035: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/netrw.vim
478.782 000.024 000.024: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/term.vim
478.944 000.059 000.059: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/ctrlp.vim
479.145 000.069 000.069: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/hunks.vim
479.471 000.120 000.120: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/whitespace.vim
479.853 000.054 000.054: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/po.vim
480.050 000.089 000.089: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/wordcount.vim
480.242 000.024 000.024: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/keymap.vim
482.185 000.073 000.073: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/section.vim
482.524 000.188 000.188: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/highlighter.vim
484.883 000.101 000.101: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/themes.vim
486.300 001.637 001.536: sourcing /home/thomas/.vim/bundle/gruvbox/autoload/airline/themes/gruvbox.vim
504.566 000.141 000.141: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/builder.vim
504.970 000.089 000.089: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/default.vim
576.879 389.599: opening buffers
577.160 000.126 000.126: sourcing /home/thomas/.vim/bundle/ctrlp.vim/autoload/ctrlp/utils.vimode
Note the big jump in clock after vim-rails, but unless I'm being dumb the self+sourced & self times are in ms right? So the clock appears to jump but without a corresponding 300ms time. Then, further down, 'opening buffers' appears to maybe account for that 300ms?
The other project is far, far worse - again, opening a single .rb file:
181.187 004.675 004.675: sourcing /home/thomas/.vim/bundle/vim-rails/autoload/rails.vim
4782.456 000.270 000.270: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions.vim
4782.607 000.053 000.053: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/quickfix.vim
4782.829 000.148 000.148: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline.vim
4782.985 000.035 000.035: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/netrw.vim
4783.113 000.024 000.024: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/term.vim
4783.280 000.059 000.059: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/ctrlp.vim
4783.479 000.070 000.070: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/hunks.vim
4783.797 000.114 000.114: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/whitespace.vim
4784.180 000.056 000.056: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/po.vim
4784.399 000.095 000.095: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/wordcount.vim
4784.598 000.026 000.026: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/keymap.vim
4786.604 000.072 000.072: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/section.vim
4786.961 000.204 000.204: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/highlighter.vim
4789.168 000.047 000.047: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/themes.vim
4790.483 001.470 001.423: sourcing /home/thomas/.vim/bundle/gruvbox/autoload/airline/themes/gruvbox.vim
4809.004 000.138 000.138: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/builder.vim
4809.359 000.078 000.078: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/default.vim
4867.585 4686.103: opening buffers
4867.862 000.126 000.126: sourcing /home/thomas/.vim/bundle/ctrlp.vim/autoload/ctrlp/utils.vim
same deal - the elapsed times don't seem to match the clock time. Looking at what's going on with the clock time it seems like vim-rails could be the culprit, but disabling it doesn't do the job, the apparent 5s jump is now at 'opening buffers':
177.576 000.045 000.045: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/themes.vim
178.888 001.464 001.419: sourcing /home/thomas/.vim/bundle/gruvbox/autoload/airline/themes/gruvbox.vim
202.604 000.145 000.145: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/builder.vim
202.975 000.074 000.074: sourcing /home/thomas/.vim/bundle/vim-airline/autoload/airline/extensions/default.vim
5496.540 5327.812: opening buffers
vim -u NONE on the same files loads blazing fast, with no particular difference between the projects, as you'd expect.
I am using the following plugins:
ctrlp.vim/ gruvbox/ vim-bundler/ vim-pug/ vim-vue/
DeleteTrailingWhitespace/ ShowTrailingWhitespace~/ vim-coffee-script/ vim-rails/
delimitMate/ typescript-vim/ vim-endwise/ vim-slim/
emmet-vim/ vim-airline/ vim-indent-guides/ vim-surround/
with Pathogen.
What's the next step in debugging this?
-u NONE
is lightning fast. No AV. Have added a paste of my bundle directory.