Linux latency measurements and compositor tuning

> While randomly closing apps, I found the culprit: the Zed editor. Apparently, an open Zed window can add latency to all my other apps even while idle in the background.

Zed definitely does funny things to KWin. It's not the only app that does, but this point in particular would be worth more investigation. I've noticed it causing weird issues with the frame pacing as well sometimes.

> I found it hard to believe we couldn’t get a wakeup timer more granular than 1 ms, so I looked at what KWin was using. Indeed, it was passing the sleep duration in milliseconds to a QBasicTimer.

I fixed the same thing in GNOME a few years ago across GLib, GTK, and Mutter/GNOME Shell. It required getting glib onto ppoll() finally.

> There it was, something about my desktop profile was introducing at least 3 ms of latency [as compared to creating a fresh account]! From here, I tried a bunch of things: plasma-manager to diff my existing profile against a clean one, removing all virtual desktops and disabling all KWin effects and any display scaling. While randomly closing apps, I found the culprit: the Zed editor. Apparently, an open Zed window can add latency to all my other apps even while idle in the background.

Things like this are so maddening. I don't worry too much about performance on Linux, reserving a Windows machine when I want full hardware acceleration and optimization.

I wonder what is Con Kolivas up to these days, he was THE og Linux ui latency guy.

It would be interesting to know if the same is true for Intel/AMD. I have one NVIDIA PC and the desktop - not even Games - feels very sluggish on GNOME - I haven't tried KDE yet. On the contrary, my AMD gaming rig subjectively feels very snappy, but I have never measured it.

These vertical labels make me unreasonably mad.

GE 10.34 released March 23th, 5 days after 10.33 - any reason to test with 10.33 in June? Was there a regression?