Profiling Vim Plugins
Updated:
I previously posted about profiling vim performance during startup.
This was useful for debugging what changes in .vimrc was expensive.
More generally, you might want to figure out which plugin is causing performance issues. And because plugins can have adverse interactions with one another, it’s not as straightforward as to add debugging in one place.
Profile
vim has :profile command, which works like a logging library.
:profile start profile.log
:profile func *
<Perform action>
:profile stop
This lets you dump logs to a file.
And you can use :profile func <PATTERN> or :profile file <PATTERN> to register what scripts or function names get logged.
Log Output
FUNCTION airline#extensions#get_loaded_extensions()
Defined: ~/.config/nvim/bundle/vim-airline/autoload/airline/extensions.vim line 499
Called 14 times
Total time: 0.000132
Self time: 0.000132
count total (s) self (s)
14 0.000115 return s:loaded_ext
FUNCTIONS SORTED ON TOTAL TIME
count total (s) self (s) function
17 0.369711 0.007703 airline#check_mode()
4 0.354932 0.040761 airline#highlighter#highlight()
212 0.225391 0.046164 airline#highlighter#exec()
340 0.200307 0.082925 airline#highlighter#get_highlight()
...
FUNCTIONS SORTED ON SELF TIME
count total (s) self (s) function
...
340 0.200307 0.082925 airline#highlighter#get_highlight()
212 0.225391 0.046164 airline#highlighter#exec()
4 0.354932 0.040761 airline#highlighter#highlight()
...
Each function is listed and it’s individual statistics are shown. This gives you a sense of how much a plugin contributes to overall performance.
The bottom 2 sections show the total time. The first is a list of functions in chronological ordering (total time). This is helpful to get a sense of sequencing. The second section shows the time a function spends. This is useful for identify functions that are expensive. Together, these two give you a pretty good idea to identify which is the baddie of the bunch.