Skip loading syntax/pandoc.vim if it's loaded #397
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I noticed that opening markdown files was slow and was trying to
optimize the startup.
When I run
echo "" > foo.md
vim --startuptime startup.log foo.md +q
I noticed in the `startup.log` that some of the heavier lines in the
trace looked redundant. Specifically, I noticed that it was running
`syntax/pandoc.vim` multiple times for multiple paths, because Neovim
seems to now distribute a `syntax/pandoc.vim` in the distribution's
`$VIMRUNTIME` path.
What's happening is that the `syntax/pandoc.vim` file loads a bunch of
other syntax files to be able to highlight embedded languages in code
blocks.
That happens every time the files are run, regardless of whether we're
already loaded a syntax definition for pandoc once, because there is no
`b:current_syntax` guard at the top of the file.
Adding the guard in this plugin doesn't actually speed anything up. The
speedup only happens when it's made both here and in the `$VIMRUNTIME`
distribution files:
❯ rg syntax/pandoc.vim startup.{old,new,both}.log
startup.old.log
272.540 025.063 003.008: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
296.343 023.082 002.412: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
297.630 000.008 000.008: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
361.296 024.097 002.412: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
385.468 023.663 002.443: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
385.853 000.007 000.007: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
146.991 028.210 003.364: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
175.621 027.840 003.237: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
176.466 000.011 000.011: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
241.812 025.036 002.764: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
269.082 026.633 003.041: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
269.506 000.009 000.009: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
startup.new.log
160.321 024.925 003.534: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
184.483 022.947 002.397: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
186.524 000.008 000.008: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
251.792 022.884 002.144: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
275.302 023.001 002.316: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
275.634 000.007 000.007: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
152.428 025.671 003.712: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
176.968 023.461 002.483: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
179.083 000.008 000.008: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
243.327 023.138 002.234: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
266.798 022.957 002.340: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
267.128 000.007 000.007: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
startup.both.log
175.965 027.418 003.803: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
177.070 000.007 000.007: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
178.088 000.009 000.009: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
242.550 024.351 002.335: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
243.092 000.006 000.006: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
243.447 000.007 000.007: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
147.441 026.421 003.213: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
148.317 000.008 000.008: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
149.163 000.010 000.010: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
219.914 026.378 002.627: sourcing /Users/jez/.config/nvim/bundle/vim-pandoc-syntax/syntax/pandoc.vim
220.423 000.006 000.006: sourcing /opt/homebrew/Cellar/neovim/0.10.4_1/share/nvim/runtime/syntax/pandoc.vim
220.797 000.010 000.010: sourcing /Users/jez/.config/nvim/after/syntax/pandoc.vim
❯ wc -l startup.{old,new,both}.log
624 startup.old.log
624 startup.new.log
520 startup.both.log
What we see happening in these files is that **only** adding the
`b:current_syntax` guard in this plugin only saves ~2ms (269ms → 267ms).
But once we add it to both the plugin and the distribution, then it
completely skips running the `syntax/pandoc.vim` the second time, which
also skips loading all the embedded syntax files (represented by a drop
in the number of entries in the startup.log files from 624 lines to 520
lines). This drops the total load time from 269ms → 220ms.
For the time being, I have manually edited my
`$VIMRUNTIME/syntax/pandoc.vim` file to also include these changes, but
it will be a subsequent priority to make sure that these plugin changes
get pulled into the distribution.
|
Note: the linter failure on this change is an infrastructure problem, not a problem with this PR. See #398. |
jez
added a commit
to jez/vim-pandoc-syntax
that referenced
this pull request
Apr 17, 2025
This was a bad merge that resulted from vim-pandoc#393 being opened before vim-pandoc#397 but landing after. If we override the `&cpo` option and then `finish`, it will never get set back to the saved cpo. Instead, let's just only do the `set` if we're sure we're not going to early exit.
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I noticed that opening markdown files was slow and was trying to
optimize the startup.
When I run
I noticed in the
startup.logthat some of the heavier lines in thetrace looked redundant. Specifically, I noticed that it was running
syntax/pandoc.vimmultiple times for multiple paths, because Neovimseems to now distribute a
syntax/pandoc.vimin the distribution's$VIMRUNTIMEpath.What's happening is that the
syntax/pandoc.vimfile loads a bunch ofother syntax files to be able to highlight embedded languages in code
blocks.
That happens every time the files are run, regardless of whether we're
already loaded a syntax definition for pandoc once, because there is no
b:current_syntaxguard at the top of the file.Adding the guard in this plugin doesn't actually speed anything up. The
speedup only happens when it's made both here and in the
$VIMRUNTIMEdistribution files:
What we see happening in these files is that only adding the
b:current_syntaxguard in this plugin only saves ~2ms (269ms → 267ms).But once we add it to both the plugin and the distribution, then it
completely skips running the
syntax/pandoc.vimthe second time, whichalso skips loading all the embedded syntax files (represented by a drop
in the number of entries in the startup.log files from 624 lines to 520
lines). This drops the total load time from 269ms → 220ms.
For the time being, I have manually edited my
$VIMRUNTIME/syntax/pandoc.vimfile to also include these changes, butit will be a subsequent priority to make sure that these plugin changes
get pulled into the distribution.