ghostty's app-ghostty-transient I/O pressure is very high ( >90% )

[randomizedcoder]

Issue Description

G'day,

I wanted to open this discussion in case anyone else is seeing something similar. I suspect this is something related to my NixOS unstable (bleeding edge), so I will continue to investigate.

The background is that a few days ago, I updated NixOS unstable and I've notice ghostty being "slow". After some investigations, I've found:

ghostty's app-ghostty-transient I/O pressure is very high ( >90% )

┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│11/04/2025 06:49:57 UTC-08:00     Elapsed: 5s     l     0.9.0     live-paused                                                                                                                                                                                │
└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│Process        Total 624    R 0      S 618    D 0      Z 6                                                                                                                                                                                                   │
│CPU            Usage    0.98%                User     0.34%                System   0.52%                                                                                                                                                                    │
│Mem            Total    125.6 GB             Free     101.7 GB             Anon     12.1 GB              File     7.6 GB                                                                                                                                     │
│VM             Page In  0.0 B/s              Page Out 42.1 KB/s            Swap In  0.0 B/s              Swap Out 0.0 B/s                                                                                                                                    │
│I/O   (Rd|Wr)  dm-0     0.0 B/s   |84.2 KB/s nvme0n1  0.0 B/s   |84.2 KB/s                                                                                                                                                                                   │
│Iface (Rx|Tx)  docker0  0.0 B     |0.0 B     enp1s0   979.5 B   |2 KB      enp65s0f00.0 B     |0.0 B     enp65s0f10.0 B     |0.0 B     lo       6.1 KB    |6.1 KB    virbr0   [...]                                                                          │
└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
┌─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│General   CPU   Mem   I/O   Pressure   Properties                                                                                                                                                                                                            │
│─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────│
│Name                                               CPU        Mem        CPU Pressure   Mem Pressure   I/O Pressure   Reads      Writes     RW Total   Nr Descendants   Nr Dying Descendants   Tids Current                                                  │
│─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────│
│   └─ prometheus-smartctl-exporter.service         0.00%      17 MB      0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      12                                                           |│
│   └─ prometheus-systemd-exporter.service          0.00%      13.9 MB    0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      6                                                            |│
│   └─ prometheus.service                           0.07%      247.6 MB   0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      29                                                           |│
│   └─ rtkit-daemon.service                         0.00%      856 KB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      3                                                            |│
│   └─ run-wrappers.mount                           0.00%      8 KB       0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      0                                                            |│
│   └─ sshd.service                                 0.00%      2.7 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            |│
│   └─ system-cups.slice                            0.00%      9.3 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    1                0                      4                                                            |│
│      └─ cups.service                              0.00%      9.3 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      4                                                            |│
│   └─ system-modprobe.slice                        0.00%      580 KB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                3                      0                                                            |│
│   └─ system-systemd\x2dcoredump.slice             0.00%      39.4 MB    0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                3                      0                                                            |│
│   └─ system-systemd\x2dfsck.slice                 0.00%      280 KB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                1                      0                                                            |│
│   └─ system-systemd\x2djournald.slice             0.00%      4.3 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    1                0                      1                                                            |│
│      └─ [email protected]            0.00%      4.3 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            |│
│   └─ system-systemd\x2djournald\x2dsync.slice     0.00%      0.0 B      0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      0                                                            |│
│   └─ system-systemd\x2djournald\x2dvarlink.slice  0.00%      0.0 B      0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      0                                                            ▒│
│   └─ systemd-journald.service                     0.00%      49.8 MB    0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            ▒│
│   └─ systemd-logind.service                       0.00%      2.8 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            ▒│
│   └─ systemd-machined.service                     0.00%      1.7 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            ▒│
│   └─ systemd-oomd.service                         0.02%      1.9 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            ▒│
│   └─ systemd-timesyncd.service                    0.00%      4.5 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      2                                                            ▒│
│   └─ systemd-udevd.service                        0.00%      41.6 MB    0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    1                0                      1                                                            ▒│
│      └─ udev                                      0.00%      ?          0.00%          0.00%          0.00%          ?          ?          ?          0                0                      ?                                                            ▒│
│   └─ udisks2.service                              0.00%      9 MB       0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      6                                                            ▒│
│   └─ upower.service                               0.01%      6.7 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      4                                                            ▒│
│   └─ usr-bin.mount                                0.00%      2.1 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      2                                                            ▒│
│   └─ virtlogd.service                             0.00%      2.7 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            ▒│
│   └─ wpa_supplicant.service                       0.00%      3.4 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      1                                                            |│
│└─ user.slice                                      7.06%      7.6 GB     0.00%          0.00%          82.12%         0.0 B/s    64.5 KB/s  64.5 KB/s  69               64                     1431                                                         |│
│   └─ user-1000.slice                              7.05%      7.4 GB     0.00%          0.00%          82.27%         0.0 B/s    64.5 KB/s  64.5 KB/s  67               47                     1431                                                         |│
│      └─ session-5.scope                           0.00%      4.7 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      18                                                           |│
│      └─ [email protected]                         7.05%      7.3 GB     0.00%          0.00%          82.55%         0.0 B/s    64.5 KB/s  64.5 KB/s  65               46                     1413                                                         |│
│         └─ app.slice                              5.17%      6.4 GB     0.00%          0.00%          85.44%         0.0 B/s    5.5 KB/s   5.5 KB/s   28               20                     1114                                                         |│
│            └─ app-com.mitchellh.ghostty.service   0.00%      15.9 MB    0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      0                                                            |│
│            └─ app-ghostty-transient-2242676.scope 4.10%      90.7 MB    0.00%          0.00%          92.42%         0.0 B/s    0.0 B/s    0.0 B/s    3                0                      40                                                           |│
│               └+ app                              1.19%      62.5 MB    0.00%          0.00%          89.31%         0.0 B/s    0.0 B/s    0.0 B/s    0                0                      31                                                           |│
│               └─ surfaces                         2.94%      28.3 MB    0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    1                0                      9                                                            |│
│                  └─ 55872D0854B0.scope            2.94%      28.3 MB    0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      9                                                            |│
│            └─ app-gnome-Alacritty-2127068.scope   0.00%      1.2 GB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      25                                                           |│
│            └─ app-gnome-Flameshot-2125476.scope   0.00%      7.5 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      9                                                            |│
│            └─ app-gnome-firefox-2146729.scope     0.81%      2.9 GB     0.00%          0.00%          0.00%          0.0 B/s    4.7 KB/s   4.7 KB/s   0                0                      813                                                          |│
│            └─ app-gnome-org.gnome.Evolution\x2dal 0.00%      8.4 MB     0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      8                                                            |│
│            └─ app-gnome-org.gnome.SettingsDaemon. 0.00%      0.0 B      0.00%          0.00%          0.00%          0.0 B/s    0.0 B/s    0.0 B/s    0                0                      4                                                            |│
│─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────│
│ full_path : /user.slice/user-1000.slice/[email protected]/app.slice/app-ghostty-transient-2242676.scope/app                                                                                                                                                 │
└─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

[das@l:~/nixos/desktop/l]$ systemctl status | grep ghostty
                 │ ├─app-ghostty-transient-2242676.scope
                 │ │ │ └─2242676 /nix/store/f1w6zhyw063pahxhi51kmppd76icjny0-ghostty-1.2.3/bin/ghostty --gtk-single-instance=true --initial-window=false
                 │ │     └─2257520 grep ghostty

[das@l:~/nixos/desktop/l]$

Maybe this relates to these?

• https://gitlab.archlinux.org/archlinux/packaging/packages/ghostty/-/issues/2
• High iowait and general slowness when using io_uring #3224

Certainly would love any advice on how to debug this in more detail

I should also mention, that I've noticed something very strange when ssh-ing to other hosts. The remote shell doesn't really work correctly sometimes. I'm still trying to understand this also. Feels like the I/O pressure is likely to be related, although ssh is weird even when not using ghostty

Expected Behavior

Low I/O Pressure, and ghostty being really fast as usual

Actual Behavior

Entire system is slow

Reproduction Steps

Start ghostty. I/O Pressure rises over perhaps ~1 minute

Ghostty Logs

[das@l:~/nixos/desktop/l]$ ghostty
info: ghostty version=1.2.3
info: ghostty build optimize=ReleaseFast
info: runtime=apprt.Runtime.gtk
info: font_backend=font.main.Backend.fontconfig_freetype
info: dependency harfbuzz=12.1.0
info: dependency fontconfig=21701
info: renderer=renderer.generic.Renderer(renderer.OpenGL)
info: libxev default backend=io_uring
info(os_locale): setlocale from env result=en_US.UTF-8
info(gtk): GTK version build=4.18.6 runtime=4.18.6
info(gtk): libadwaita version build=1.7.6 runtime=1.7.6
info: reading configuration file path=/home/das/.config/ghostty/config
info(config): default shell src=passwd value=/run/current-system/sw/bin/bash
info(config): default working directory src=passwd value=/home/das
warning(gtk_ghostty_application): setting GDK_DEBUG=
warning(gtk_ghostty_application): setting GDK_DISABLE=gles-api,vulkan
info(gtk_systemd_cgroup): transient scope created cgroup=/user.slice/user-1000.slice/[email protected]/app.slice/app-ghostty-transient-2271148.scope
info(gtk_ghostty_application): cgroup isolation enabled base=/user.slice/user-1000.slice/[email protected]/app.slice/app-ghostty-transient-2271148.scope
info(opengl): loaded OpenGL 4.6
info(io_exec): found Ghostty resources dir: /nix/store/f1w6zhyw063pahxhi51kmppd76icjny0-ghostty-1.2.3/share/ghostty
info(io_exec): shell integration automatically injected shell=termio.shell_integration.Shell.bash
warning(gtk_ghostty_application): unimplemented action=apprt.action.Action.Key.cell_size
info(io_exec): started subcommand path=/run/current-system/sw/bin/bash pid=2271220
info(io_exec): subcommand cgroup=/user.slice/user-1000.slice/[email protected]/app.slice/app-ghostty-transient-2271148.scope/surfaces/55AC8E7CF3A0.scope
warning(stream): unimplemented OSC callback: terminal.osc.Command{ .end_of_command = terminal.osc.Command__struct_253468{ .exit_code = 0 } }
warning(stream): unimplemented OSC command: end_of_command

### Ghostty Version

```text
[das@l:~]$ ghostty +version
Ghostty 1.2.3

Version
  - version: 1.2.3
  - channel: stable
Build Config
  - Zig version   : 0.14.1
  - build mode    : builtin.OptimizeMode.ReleaseFast
  - app runtime   : apprt.Runtime.gtk
  - font engine   : font.main.Backend.fontconfig_freetype
  - renderer      : renderer.generic.Renderer(renderer.OpenGL)
  - libxev        : io_uring
  - kernel version: 6.17.7
  - desktop env   : gnome
  - GTK version   :
    build         : 4.18.6
    runtime       : 4.18.6
  - libadwaita    : enabled
    build         : 1.7.6
    runtime       : 1.7.6
  - libX11        : enabled
  - libwayland    : enabled

[das@l:~]$ neofetch
          ▗▄▄▄       ▗▄▄▄▄    ▄▄▄▖            das@l
          ▜███▙       ▜███▙  ▟███▛            -----
           ▜███▙       ▜███▙▟███▛             OS: NixOS 25.11.20251102.b3d51a0 (Xantusia) x86_64
            ▜███▙       ▜██████▛              Host: LENOVO 1046
     ▟█████████████████▙ ▜████▛     ▟▙        Kernel: 6.17.7
    ▟███████████████████▙ ▜███▙    ▟██▙       Uptime: 10 hours, 12 mins
           ▄▄▄▄▖           ▜███▙  ▟███▛       Packages: 1150 (nix-system), 1742 (nix-user)
          ▟███▛             ▜██▛ ▟███▛        Shell: bash 5.3.3
         ▟███▛               ▜▛ ▟███▛         Resolution: 3840x2160, 5120x1440, 3840x2160
▟███████████▛                  ▟██████████▙   DE: GNOME 48.4 (Wayland)
▜██████████▛                  ▟███████████▛   Theme: Nordic [GTK2/3]
      ▟███▛ ▟▙               ▟███▛            Icons: Papirus-Dark [GTK2/3]
     ▟███▛ ▟██▙             ▟███▛             Terminal: ghostty
    ▟███▛  ▜███▙           ▝▀▀▀▀              CPU: AMD Ryzen Threadripper PRO 3945WX s (24) @ 4.427GHz
    ▜██▛    ▜███▙ ▜██████████████████▛        GPU: AMD ATI Radeon Pro VII/Radeon Instinct MI50 32GB
     ▜▛     ▟████▙ ▜████████████████▛         GPU: AMD ATI Radeon Pro W5700
           ▟██████▙       ▜███▙               Memory: 16035MiB / 128659MiB
          ▟███▛▜███▙       ▜███▙
         ▟███▛  ▜███▙       ▜███▙
         ▝▀▀▀    ▀▀▀▀▘       ▀▀▀▘

[das@l:~/nixos/desktop/l]$ uname -a
Linux l 6.17.7 #1-NixOS SMP PREEMPT_DYNAMIC Sun Nov  2 13:18:05 UTC 2025 x86_64 GNU/Linux

### OS Version Information

NixOS unstable b3d51a0365f6695e7dd5cdf3e180604530ed33b4

### (Linux only) Display Server

Wayland

### (Linux only) Desktop Environment/Window Manager

GNOME Shell 48.4

### Minimal Ghostty Configuration

```ini
https://github.com/randomizedcoder/nixos/blob/ghostty/desktop/l/home.nix#L10


home.nix
{
  config,
  pkgs,
  ...
}:

{
  # Ghostty configuration
  programs.ghostty = {
    enable = true;
    # settings = {
    # settings doesn't work
  };
...

[das@l:~]$ cat .config/ghostty/config
# This is the configuration file for Ghostty.
#
# This template file has been automatically created at the following
# path since Ghostty couldn't find any existing config files on your system:
#
#   /home/das/.config/ghostty/config
#
# The template does not set any default options, since Ghostty ships
# with sensible defaults for all options. Users should only need to set
# options that they want to change from the default.
#
# Run `ghostty +show-config --default --docs` to view a list of
# all available config options and their default values.
#
# Additionally, each config option is also explained in detail
# on Ghostty's website, at https://ghostty.org/docs/config.
#
# Ghostty can reload the configuration while running by using the menu
# options or the bound key (default: Command + Shift + comma on macOS and
# Control + Shift + comma on other platforms). Not all config options can be
# reloaded while running; some only apply to new windows and others may require
# a full restart to take effect.

# Config syntax crash course
# ==========================
# # The config file consists of simple key-value pairs,
# # separated by equals signs.
# font-family = Iosevka
# window-padding-x = 2
#
# # Spacing around the equals sign does not matter.
# # All of these are identical:
# key=value
# key= value
# key =value
# key = value
#
# # Any line beginning with a # is a comment. It's not possible to put
# # a comment after a config option, since it would be interpreted as a
# # part of the value. For example, this will have a value of "#123abc":
# background = #123abc
#
# # Empty values are used to reset config keys to default.
# key =
#
# # Some config options have unique syntaxes for their value,
# # which is explained in the docs for that config option.
# # Just for example:
# resize-overlay-duration = 4s 200ms

[das@l:~]$

### Additional Relevant Configuration


Entire system config is here:
https://github.com/randomizedcoder/nixos/tree/ghostty/desktop/l
https://github.com/randomizedcoder/nixos/blob/ghostty/desktop/l/flake.nix

Tagged:
https://github.com/randomizedcoder/nixos/releases/tag/ghostty

### I acknowledge that:

- [X] I have reviewed the FAQ and confirm that my issue is NOT among them.
- [X] I have searched the Ghostty repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
- [X] I have checked the "Preview" tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks with a group of three backticks (` ``` `) on separate lines.

[rhodes-b]

if you swap the async-backend to epoll and it goes away its one of the discussions you referenced above. Please try that

[rhodes-b]

the ssh problem could be this
https://ghostty.org/docs/help/terminfo

if its happening in general though not just ghostty then its not a a ghostty problem

[rhodes-b]

There was also previously a kernel problem with io_uring read this. Your version is past this but some new regression could have been introduced
#7720

[randomizedcoder]

Thanks for the replies!

I rolled back the kernel to nixpkgs pkgs.linuxPackages ( which is 6.12.57 )

  boot = {

    kernelPackages = pkgs.linuxPackages;
    #kernelPackages = pkgs.linuxPackages_latest;
...

[das@l:~]$ uname -a
Linux l 6.12.57 #1-NixOS SMP PREEMPT_DYNAMIC Sun Nov  2 13:15:23 UTC 2025 x86_64 GNU/Linux

But the I/O Pressure is still there

The I/O Pressure takes ~1m15s to raise

The Prometheus query for this is:

rate(node_pressure_io_stalled_seconds_total{instance="$node",job="$job"}[$__rate_interval])

Therefore, I'm guessing this isn't kernel version, although possibly GPU related. I don't see anything nasty in dmesg.

[das@l:~]$ rocm-smi


=========================================== ROCm System Management Interface ===========================================
===================================================== Concise Info =====================================================
Device  Node  IDs              Temp    Power     Partitions          SCLK    MCLK    Fan     Perf  PwrCap  VRAM%  GPU%
              (DID,     GUID)  (Edge)  (Socket)  (Mem, Compute, ID)
========================================================================================================================
0       2     0x66a1,   33678  47.0°C  20.0W     N/A, N/A, 0         938Mhz  350Mhz  14.51%  auto  225.0W  0%     0%
1       1     0x7312,   11012  61.0°C  35.0W     N/A, N/A, 0         800Mhz  900Mhz  20.0%   auto  140.0W  23%    3%
========================================================================================================================
================================================= End of ROCm SMI Log ==================================================

And the related ssh issue: A small discovery is that xterm seems to be "ok". ghostty, gnome-terminal, and kitty, all seem to be impacted. Although, I had a gnome-terminal ssh-ed to the same machine. One ssh was working ok and the other not. I need to perform more testing...

[randomizedcoder]

Interesting. I wonder if the I/O pressure issue is actually causing the ssh issue?

When turning off SSH ControlMaster and ControlPath, ssh comes good.

        #ControlMaster auto
        #ControlPath ~/.ssh/master-%r@%h:%p
        #ControlPersist 10m

~/.ssh/config

Host *
        User das
        KeepAlive yes
        ServerAliveInterval 30
        Protocol 2
        #UseRoaming no
        ForwardAgent yes
        # Modern Key Exchange Algorithms (Kex) - Prioritizes Post-Quantum (if available) and Curve25519
        KexAlgorithms [email protected],[email protected],curve25519-sha256,diffie-hellman-group-exchange-sha256
        # Modern Ciphers - Prioritizes ChaCha20 and AES-GCM (Authenticated Encryption)
        Ciphers [email protected],[email protected],[email protected]
        # Modern MACs - Prioritizes Encrypt-then-MAC (EtM) modes
        MACs [email protected],[email protected],[email protected]
        # temp hmac-md5
        #MACs [email protected],[email protected],[email protected],hmac-sha2-512,hmac-sha2-256,hmac-md5
        #ControlMaster auto                                        <----- disabled
        #ControlPath ~/.ssh/master-%r@%h:%p         <----- disabled
        #ControlPersist 10m                                        <----- disabled
        Compression yes
        ConnectTimeout 10
        HashKnownHosts no

This works great.

I tried moving ControlPath to /run/user/$(id -u)/ssh, but it still fails.

[das@l:~/nixos/desktop/l]$ ssh -vv hp2
debug1: OpenSSH_10.1p1, OpenSSL 3.6.0 1 Oct 2025
debug1: Reading configuration data /home/das/.ssh/config
debug1: /home/das/.ssh/config line 3: Applying options for *
debug1: /home/das/.ssh/config line 47: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /nix/store/arsgpndp7kwjxbx1d5qk6hy4s9xq1y1n-libvirt-11.7.0/etc/ssh/ssh_config.d/30-libvirt-ssh-proxy.conf
debug2: checking match for 'host * exec "/nix/store/ciarnmsx8lvsrmdbjddpmx0pqjrm8imb-bash-5.3p3/bin/bash -c '/nix/store/g4qc9abpqsj1ibfi2z5mavkw9s6fglwh-gnupg-2.4.8/bin/gpg-connect-agent --quiet updatestartuptty /bye >/dev/null 2>&1'"' host hp2 originally hp2
debug1: Executing command: '/nix/store/ciarnmsx8lvsrmdbjddpmx0pqjrm8imb-bash-5.3p3/bin/bash -c '/nix/store/g4qc9abpqsj1ibfi2z5mavkw9s6fglwh-gnupg-2.4.8/bin/gpg-connect-agent --quiet updatestartuptty /bye >/dev/null 2>&1''
debug2: match found
debug1: /etc/ssh/ssh_config line 9: Applying options for *
debug1: Reading configuration data /nix/store/f8plklbbq3gwkq1wfq89i3f4wy8rabzn-systemd-258/lib/systemd/ssh_config.d/20-systemd-ssh-proxy.conf
debug2: fd 3 setting O_NONBLOCK
debug1: mux_client_hello_exchange: read packet failed                        <----- :(
muxclient: master hello exchange failed