#TUI lag

1 messages · Page 1 of 1 (latest)

sharp monolith
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hmm - does it flicker? or just get really laggy?

void valley
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not laggy. flicker is the word I was looking for. It's jarringly flickery when verbosity goes up

sharp monolith
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that's weird, it's supposed to be using terminal synchronization primitives to avoid that

void valley
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Do you have a good rec for a screen recorder for mac? I can record try to record it

sharp monolith
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i think quicktime can do it

void valley
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It happened both on my work laptop and persona. They are both M4 macs though

sharp monolith
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trying to repro in ghostty, nothing yet - i'm on linux, can try a mac tomorrow

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if i run anything huge like dagger checks --scale-out in dagger (~50 checks) on max verbosity, it does start to lag a bit, but i don't see the churning in that video

void valley
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ooh, forgot to mention. I'm on tmux. Let me try on just ghostty

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That's it. Just ghostty is much better. So the issue is with tmux :(. The previous TUI didn't have the flicker though.

sharp monolith
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Ah interesting - do you have a scrollback limit in tmux?

void valley
sharp monolith
void valley
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That's exactly what I'm seeing. It's crippling tbh. I can't take my eyes off of it sometimes 😄

sharp monolith
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for context, this goes hand in hand with preserving scrollback, which is one of the main features of the new framework. unfortunately when the output exceeds screen height, and content above the viewport has to change, the only real option is to clear and repaint. if the terminal emulator supports synchronized output (ghostty, any good terminal in 2026) you won't notice it happening, but it looks like tmux doesn't support synchronized output: https://github.com/tmux/tmux/issues/4299

though it does look like they merged support for it into master but maybe it hasn't shipped yet? https://github.com/tmux/tmux/commit/1c7e164c22a3cb21d1e281087cd4aaa489d72b84

sharp monolith
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will look into it soon, thanks for the report and sorry about that! likely need to just go into a less ambitious mode when running in tmux, or minimize offscreen updates for spinners etc. - i'll iterate and try not to sacrifice too much, tmux is important

void valley
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Thank you! I have't found a good enough alternative. I'm eagerly waiting on ghostty to add session management.

shut portal
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FWIW this seems to also impact my nvim terminals (which share the same sort of problems as tmux afaik)

sharp monolith
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makes sense yeah

shut portal
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maybe over the weekend I'll try "codex, implement synchronized output support for neovim terminals, then update my dev environment to build and use that fork" 😄

void valley
sharp monolith
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@void valley here's a PR if you want to try out a local build (if it's worth the trouble)

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now it detects when sync write support is missing and limits the UI to the viewport, using an alt screen

void valley
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I can test on my personal Mac. What's the PR?

sharp monolith