Slow Startup Time on Linux

[javacafe01]

First of all, I want to say what a great and feature rich terminal emulator wezterm is. I can't believe I've never heard about this until the latest r/unixporn post about it.

My startup times for wezterm have been pretty slow. Using time wezterm start echo hi, I get around 0.38s for user time, and 0.15s for system time. I just want to make sure if there aren any extra config options that I can disable to speed up performance, or if I'm doing something wrong.

Info:

• Arch Linux X11
• wezterm nightly from the AUR

Config

RUST_LOG=trace wezterm 2> /tmp/startup.log

Thanks!

(Also, is there a way I can disable the prompt when I quit? I searched through docs, maybe I have to search more.)

[wez]

For the startup logging, I'm pleased that you found the RUST_LOG=trace thing, but that was changed to WEZTERM_LOG=trace in an earlier release; would you mind re-running and collecting that?

Some arch users have reported that the nightly and bin AURs (which are really running binaries from an older debian release) run slower than using the built-from-source git AUR. Would you mind giving the latter a try?

Re: close confirmation there are a couple of related options:

• You can set window_close_confirmation = "NeverPrompt". See: https://wezfurlong.org/wezterm/config/lua/config/window_close_confirmation.html
• You can set a key binding that uses CloseCurrentTab, and the confirm option there. There is also a confirm option for CloseCurrentPane which you may also want!

[undefinedDarkness]

I wasnt sure how to comment without answering heh,
This term is excellent and amazing

I have been experiancing the same slow startup time but using the app image on ubuntu 20.04 LTS

Also curiously wezterm start exit which I would expect to just start the term and then exit, makes wezterm freak out

$ time wezterm start echo hi

real    0m0.977s
user    0m0.187s
sys     0m0.136s
$ time st -e echo hi

real    0m0.062s
user    0m0.036s
sys     0m0.026s

These are my results
I tried installing kitty to compare but ubuntu repos derped for some reason

Wzterm trace output:
here

I havent made a wezterm config yet 😅
Really cool project tho

[javacafe01]

@wez Thanks for the quick reply! After installing it with the build-from-source git AUR, I'm getting around 0.33s for user time and around 0.29s for system time.

Here is the new log.

[wez]

2021-03-17T14:37:28.368Z TRACE wezterm_font::locator::font_config > best match took 120.886462ms to compute and is Pattern(DejaVu Sans:style=Book:slant=0:weight=80:spacing=100:file=/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf:index=0:charset=

It appears to be a font-config issue; it took font config 120ms to load and generate that first result.

Things to try to help understand the issue; try them one at a time:

• Rebuild the font config cache: fc-cache -f -v to see if that helps
• Try starting wezterm using wezterm '--config font_locator="ConfigDirsOnly"' which will ignore font config and use only explicitly configured font_dirs. font_locator font_dirs
• Try installing JetBrains Mono so that font-config can potentially find it faster (I don't like this as a solution, but it is something to try)

[wez]

@javacafe01 for you, the first paint takes 248ms:

 2021-03-17T14:39:49.989Z TRACE wezterm_font::shaper::harfbuzz     > [OnDisk { path: "/usr/share/fonts/sarasa-gothic/sarasa-bold.ttc", index: 24 }, OnDisk { path: "/usr/share/fonts/sarasa-gothic/sarasa-bold.ttc", index: 24 }, OnDisk { path: "/usr/share/fonts/OTF/Fira Code Bold Nerd Font Complete Mono.otf", index: 0 }, OnDisk { path: "/usr/share/fonts/OTF/Fira Code Bold Nerd Font Complete Mono.otf", index: 0 }, OnDisk { path: "/usr/share/fonts/TTF/JetBrainsMono-Regular.ttf", index: 0 }, OnDisk { path: "/usr/share/fonts/TTF/JetBrainsMono-Regular.ttf", index: 0 }, Memory { name: "../../assets/fonts/NotoColorEmoji.ttf", data_len: 7253060, index: 0 }, Memory { name: "../../assets/fonts/LastResortHE-Regular.ttf", data_len: 502504, index: 0 }]
 2021-03-17T14:39:49.989Z TRACE wezterm_font::shaper::harfbuzz     > shaper wants 0 OnDisk { path: "/usr/share/fonts/sarasa-gothic/sarasa-bold.ttc", index: 24 }
 2021-03-17T14:39:50.015Z TRACE wezterm_font::ftwrap               > Loading /usr/share/fonts/sarasa-gothic/sarasa-bold.ttc for freetype!
 2021-03-17T14:39:50.015Z DEBUG wezterm_font::ftwrap               > set_char_size computing 12 dpi=96
 2021-03-17T14:39:50.017Z TRACE wezterm_font::shaper::harfbuzz     > metrics: FontMetrics { cell_width: 8.0, cell_height: 20.000040531158447, descender: -5.0, underline_thickness: 0.8000016212463379, underline_position: -1.2000024318695068 }
 2021-03-17T14:39:50.018Z TRACE wezterm_font::rasterizer::freetype > Rasterizier wants OnDisk { path: "/usr/share/fonts/sarasa-gothic/sarasa-bold.ttc", index: 24 }
 2021-03-17T14:39:50.043Z TRACE wezterm_font::ftwrap               > Loading /usr/share/fonts/sarasa-gothic/sarasa-bold.ttc for freetype!
 2021-03-17T14:39:50.043Z DEBUG wezterm_font::ftwrap               > set_char_size computing 12 dpi=96
 2021-03-17T14:39:50.045Z TRACE wezterm_font::shaper::harfbuzz     > shaper wants 1 OnDisk { path: "/usr/share/fonts/sarasa-gothic/sarasa-regular.ttc", index: 24 }
 2021-03-17T14:39:50.071Z TRACE wezterm_font::ftwrap               > Loading /usr/share/fonts/sarasa-gothic/sarasa-regular.ttc for freetype!
 2021-03-17T14:39:50.071Z DEBUG wezterm_font::ftwrap               > set_char_size computing 12 dpi=96
 2021-03-17T14:39:50.074Z TRACE wezterm_font::shaper::harfbuzz     > shaper wants 2 OnDisk { path: "/usr/share/fonts/OTF/Fira Code Regular Nerd Font Complete Mono.otf", index: 0 }
 2021-03-17T14:39:50.075Z TRACE wezterm_font::ftwrap               > Loading /usr/share/fonts/OTF/Fira Code Regular Nerd Font Complete Mono.otf for freetype!
 2021-03-17T14:39:50.075Z DEBUG wezterm_font::ftwrap               > set_char_size computing 12 dpi=96
 2021-03-17T14:39:50.075Z TRACE wezterm_font::rasterizer::freetype > Rasterizier wants OnDisk { path: "/usr/share/fonts/OTF/Fira Code Regular Nerd Font Complete Mono.otf", index: 0 }
 2021-03-17T14:39:50.076Z TRACE wezterm_font::ftwrap               > Loading /usr/share/fonts/OTF/Fira Code Regular Nerd Font Complete Mono.otf for freetype!
 2021-03-17T14:39:50.077Z DEBUG wezterm_font::ftwrap               > set_char_size computing 12 dpi=96
 2021-03-17T14:39:50.077Z TRACE wezterm_font::shaper::harfbuzz     > metrics: FontMetrics { cell_width: 10.0, cell_height: 19.692420959472656, descender: -5.0, underline_thickness: 0.41025876998901367, underline_position: -0.8205175399780273 }
 2021-03-17T14:39:50.077Z TRACE wezterm_gui::glyphcache            > physically scaling GlyphInfo { is_space: false, cluster: 0, num_cells: 1, font_idx: 2, glyph_pos: 3735, x_advance: 10.0, y_advance: 0.0, x_offset: 0.0, y_offset: 0.0 } by 0.8 bcos 10x12 > 8.0x20.000040531158447
 2021-03-17T14:39:50.077Z TRACE wezterm_gui::glyphcache            > GlyphInfo { is_space: false, cluster: 0, num_cells: 1, font_idx: 2, glyph_pos: 3735, x_advance: 10.0, y_advance: 0.0, x_offset: 0.0, y_offset: 0.0 } CachedGlyph { has_color: false, x_offset: 0.0, y_offset: 0.0, bearing_x: 0.0, bearing_y: 8.8, scale: 1.0, texture: Some(Sprite { coords: Rect(8x9 at (19, 16)), texture_width: 128, texture_height: 128 }) }
 2021-03-17T14:39:50.078Z DEBUG wezterm_gui::termwindow::render    > paint_pane_opengl elapsed=248.818746ms

(that config doesn't match the one in your OP!)

This is likely a function of the mixture of fonts and the text that is initially being displayed by your shell startup. Would you mind comparing the startup time against:

default wezterm config with no bashrc:

wezterm -n start -- bash --norc

your wezterm config, with no bashrc:

wezterm start -- bash --norc

[javacafe01]

@wez I changed the fonts in my config after I posted them and before I replied to you 😄 . I took your advice and did a simple fc-cache -fv, which reduced my time to 0.15s user and 0.17s system! Thanks for your quick reply and help.