yabai query taking ~8 seconds to return

[eraserhd]

I'm integrating with Kitty, and making a "kitten" to allow things connected to the tty to query their pixel position on the display. The kitten's code is very simple:

from kittens.tui.handler import result_handler
import subprocess
import json
import time

def main(args):
    pass

@result_handler(no_ui=True)
def handle_result(args, answer, target_window_id, boss):
    w = boss.window_id_map.get(target_window_id)
    if w is None:
        return ""
    a = time.time()
    os_window_id = w.child.environ.get("WINDOWID")
    if os_window_id is None:
        return ""
    b = time.time()
    data = json.loads(subprocess.check_output(["yabai", "-m", "query", "--windows", "--window", str(os_window_id)]))
    c = time.time()
    return str({'a': a, 'b': b, 'c': c, 'data': data["frame"]})

I get this output:

$ kitty @ kitten window_position.py
{'a': 1595951330.027246, 'b': 1595951330.027334, 'c': 1595951338.6383119, 'data': {'x': 2880.0, 'y': 704.0, 'w': 958.0, 'h': 699.0}}

During the delay, yabai commands hang and queue up (for example my skhd bindings to switch windows, which use yabai --focus, wait until the result returns).

If I replace the command with ls -l, it responds immediately. I isolated the JSON parsing, and that isn't taking any time.

I can't think of anything that causes this. I suspect the kitten runs detached from any terminal. I just tried to make it a "UI kitten", which gives it a tty, but that doesn't change anything.

[koekeishiya]

I have no idea how the python subprocess module is implemented so I cannot really help here.

Running from a CLI works fine and I also have personal projects that call yabai's query system using popen from C and that also finishes instantaneously.

~ time yabai -m query --windows --window 3278                                                                                                                                                                 
{
        "id":3278,
        "pid":1548,
        "app":"kitty",
        "title":"tmux",
        "frame":{
                "x":12.0000,
                "y":34.0000,
                "w":1416.0000,
                "h":854.0000
        },
        "level":0,
        "role":"AXWindow",
        "subrole":"AXStandardWindow",
        "movable":1,
        "resizable":1,
        "display":1,
        "space":1,
        "visible":1,
        "focused":1,
        "split":"none",
        "floating":0,
        "sticky":0,
        "minimized":0,
        "topmost":0,
        "opacity":1.0000,
        "shadow":0,
        "border":1,
        "stack-index":0,
        "zoom-parent":0,
        "zoom-fullscreen":0,
        "native-fullscreen":0
}
yabai -m query --windows --window 3278  0.01s user 0.00s system 78% cpu 0.011 total

[spolakh]

Not sure if it's related, but for me even the CLI execution delay varies wildly - at times it's instantaneous and at times it takes seconds to run (even when overall cpu usage is under 30%). Example: https://giphy.com/gifs/LkkNVInM528mPQLXJU

Makes querying pretty much unusable in shortcuts

Catalina, 10.15.6
Scripting addition enabled

[koekeishiya]

This could be because of reasons described in #599 / #600.
Basically the AX API is blocking and if the target application is slow to respond, that will ultimately be the bottleneck of how responsive yabai can be.

[slam]

FWIW, I ran into the same issue where yabai -m query --windows would be slow sometimes. When it was slow it was always about 8 seconds. I captured the output when it was fast vs slow, and here is a clue. (/tmp/x is fast, and /tmp/x2 is slow):

➜   diff /tmp/x /tmp/x2
69c69
<   "title":"Activity Monitor (All Processes)",
---
>   "title":"",
77,80c77,80
<   "role":"AXWindow",
<   "subrole":"AXStandardWindow",
<   "movable":1,
<   "resizable":1,
---
>   "role":"",
>   "subrole":"",
>   "movable":0,
>   "resizable":0,

I restarted Activity Monitor and the slowness went away.