alacritty: Alacritty is consistently slower than urxvt in XQuartz (macOS)

Alacritty’s biggest claim is that it’s the fastest terminal emulator available. If there’s a case where it’s not, then it’s either a bug in Alacritty or a misconfigured system

After a fresh install of Alacritty on OS X, I generated a 38MB text file consisting of 10 million lines of “foo” with the command printf "%0.sfoo\n" {1..10000000} > 10mil.txt and then attempted to compare the speed of Alacritty to the speed of urxvt running in Xquartz by running time cat 10mil.txt a few times in each terminal at a normal size after priming caches.

Times taken in urxvt 2.833s 2.966s 2.555s Times taken in alacritty 5.611s 5.665s 5.553s

Alacritty’s performance scales well with screen size. Running at larger resolutions will tip the scale further in Alacritty’s favor.

Times taken in urxvt (full screen) 3.348s 3.614s 3.639s Times taken in alacritty (full screen) 12.819s 12.641s 13.320s

I normally wouldn’t consider this a bug, but I figure you probably want all the comparisons you can get if you’re trying to make alacritty the fastest terminal emulator. Also thought it was better to open a new issue rather than commenting on an existing performance issue both for organization and because the root causes might be totally different.

Let me know if there’s any additional information you’d like me to provide.

Edit:

$ glxinfo | grep OpenGL
OpenGL vendor string: NVIDIA Corporation
OpenGL renderer string: NVIDIA GeForce 320M OpenGL Engine
OpenGL version string: 2.1 NVIDIA-10.2.12 310.90.10.05b20
OpenGL shading language version string: 1.20
OpenGL extensions: