I don’t think he should have included the starting frame-- if the cursor were theoretically instant, his method records it with a 1 frame delay, and this +1 frame error happens on every test. Correcting this actually makes Wayland more laggy proportionally, although it makes both less laggy absolutely.
What I’ve noticed with Wayland in Plasma is that it’s very much tied to my monitors refresh rate.
At 240Hz, with adaptive sync turned off or to Automatic, I get a very responsive cursor.
At 75Hz, or if I force adaptive sync to be on at all times (instead of off or Automatic), then I get a noticeable mouse latency
Latency raw data :
Gnome Variant Δ camera frames Average (Δ) Δ milli seconds Δ monitor refreshes X11 5 4 3 4 5 4 6 5 1 4 4 4 3 4 4 4 4.00 16.7 2.4 Wayland 6 5 6 5 5 6 6 4 8 6 5 5 5 6 5 6 5.5625 23.2 3.3 Δ(Δ) - - ~1.5 ~6.5 ~1.0 instead of calculating the average one could decide to drop the data points that are way outside of their goups.
Doing so, in the first group I would neglect the value of Δ = 1 or 6 frame and in the second group I would neglect the value of 4 or 8 framesResults :
X11 : from 3 to 5 frames
Wayland : from 5 to 6 frames
Δ(Δ) = 5.5 - 4 = 1.5Still it doesn’t change the final result that the difference between these two Gnome versions is 1.5 camera frames at 240 frames per second.
Good analysis
Thanks. Also, after a bit of thought, i do believe you are right saying that we should remove one frame of all the raw camera data. … it will, as you say, decrease the absolute values and make Wayland more laggy proportionally, yet, it doesn’t change the absolute difference.
I saw some cheap laptops with Ubuntu in a local mall and on them the latency on Wayland was unbearable.