Is there a way to limit the amount of scrollback lines fed to kitty-scrollback specifically?

[J-Kappes]

I like having the option to scroll back 10k lines in kitty itself or with less, but when I want to yank something it's usually pretty recent, and I get the impression the scrollback size contributes to slow startup.

[mikesmithgh]

Hey @J-Kappes, could you provide the output of :KittyScrollbackCheckHealth. I'd like to view some of those configs.

Is there a way to limit the amount of scrollback lines fed to kitty-scrollback specifically?

Yes, I have been neglecting some documentation #4 😹

My current and recommended kitty.conf settings are:

scrollback_pager_history_size 2

• scrollback_pager_history_size controls the amount of history that is stored and passed to scrollback pager programs like kitty-scrollback.nvim or less. From the docs:

The current implementation stores the data in UTF-8, so approximately 10000 lines per megabyte at 100 chars per line, for pure ASCII, unformatted text.

• I pick 2 here because 2 mb is approximately 20000 lines (actually less than 20000 due to ANSI formatting) which seems like a reasonably large amount of history to me.
  scrollback_fill_enlarged_window yes

scrollback_lines 2000

• scrollback_lines controls the number of lines visible in your Kitty terminal session (not a pager like less or kitty-scrollback.nvim). I just left as the default value 2000

Neovim allows for the maximum of 100000 lines in its terminal buffer (which kitty-scrollback.nvim uses). See vim.o.scrollback

My guess is that you may have a large number for scrollback_pager_history_size which is causing the slow startup time for kitty-scrollback.nvim.

Hopefully this helps. I am interested in the results of :KittyScrollbackCheckHealth and if changing any of those values help. There is also a show_timer option in kitty-scrollback.nvim's config

        status_window = {
          show_timer = true,
        },

if you set that to true, it will show a timer while kitty is loading to get a rough number of how long it is taking.

[J-Kappes]

Here's my output before changing anything:
https://gist.github.com/J-Kappes/02fa67c371b7356efe4f2b97b0e44206

So if understand correctly, the only way of limiting kitty-scrollback's buffer also limits less's? That's too bad because I get no noticeable delay when starting less and I like using it to find stuff from far back.

[mikesmithgh]

well that is to limit to any scrollback pager, so yes less or kitty-scrollback.nvim. I am confused though, because your config has
scrollback_pager_history_size = 0
so I wouldn't expect you to have much in your pager scrollback at all?

I don't see any difference at least on my machine with less and kitty-scrollback.nvim for large scrollbacks.

What type of delay are we talking about ms or seconds? It might be helpful you could capture a video I may be missing something.

[J-Kappes]

ms. They're pretty noticable though, since the terminal goes blank for the duration. Here's a video of me starting less followed by nvim.

Screencast.from.2023-12-01.10-01-00.webm

[mikesmithgh]

@J-Kappes thanks for the video, that helps! Yes, that is expected/current behavior at the moment.

I agree it would be nice to have it transition as quickly as less. I think I'd have to experiment with some caching or background process to get it to the same speed as less.