4.1 KiB
Benchmarks
vtebench
All benchmarks are done using vtebench:
vtebench -h $(tput lines) -w $(tput cols) -b 104857600 alt-screen-random-write > ~/alt-random
vtebench -c -h $(tput lines) -w $(tput cols) -b 104857600 alt-screen-random-write > ~/alt-random-colors
vtebench -h $(tput lines) -w $(tput cols) -b 10485760 scrolling > ~/scrolling
vtebench -h $(tput lines) -w $(tput cols) -b 104857600 scrolling --fill-lines > ~/scrolling-filled-lines
vtebench -h $(tput lines) -w $(tput cols) -b 10485760 unicode-random-write > ~/unicode-random
They were "executed" using benchmark.py, which will load each file into memory, and then print it to the terminal. This is done 20 times for each test. Then it calculates the mean and standard deviation for each test.
2020-10-09
System
CPU: i9-9900
RAM: 64GB
Graphics: Radeon RX 5500XT
Terminal configuration
Geometry: 2040x1884
Font: Fantasque Sans Mono 10.00pt/23px
Scrollback: 10000 lines
Results
| Benchmark | Foot (GCC+PGO) 1.5.0.r90 | Foot 1.5.0.r90 | Alacritty 0.5.0 | URxvt 9.22 | XTerm 360 |
|---|---|---|---|---|---|
| alt-random | 0.353s ±0.007 | 0.685s ±0.005 | 0.903s ±0.011 | 1.102s ±0.004 | 12.886s ±0.064 |
| alt-random-colors | 0.354s ±0.019 | 0.665s ±0.004 | 0.933s ±0.004 | 1.149s ±0.013 | 11.739s ±0.093 |
| scrolling | 1.387s ±0.077 | 1.257s ±0.032 | 1.048s ±0.011 | 1.001s ±0.023 | 38.187s ±0.192 |
| scrolling-filled-lines | 0.607s ±0.008 | 0.834s ±0.038 | 1.246s ±0.020 | 1.224s ±0.008 | 6.619s ±0.166 |
| unicode-random | 0.224s ±0.001 | 0.144s ±0.001 | 0.092s ±0.004 1 | 21.294s ±1.580 | 26.594s ±3.801 |
2020-12-21
System
CPU: i5-8250U
RAM: 8GB
Graphics: Intel UHD Graphics 620
Terminal configuration
Geometry: 945x1020
Font: Dina:pixelsize=12
Scrollback=10000 lines
Results
| Benchmark | Foot (GCC+PGO) 1.6.0.r30 | Foot (no PGO) 1.6.0.r30 | Alacritty 0.6.0 | URxvt 9.22 | St 0.8.4 | XTerm 362 |
|---|---|---|---|---|---|---|
| alt-random | 0.734s ±0.051 | 1.186s ±0.101 | 1.580s ±0.083 | 1.709s ±0.090 | 1.953s ±0.038 | 38.693s ±0.298 |
| alt-random-colors | 0.728s ±0.047 | 1.267s ±0.090 | 1.579s ±0.073 | 2.108s ±0.121 | 2.185s ±0.099 | 34.123s ±0.194 |
| scrolling | 1.639s ±0.040 | 1.641s ±0.053 | 1.397s ±0.048 | 1.389s ±0.046 | 3.599s ±0.124 | 136.514s ±0.534 |
| scrolling-filled-lines | 1.328s ±0.050 | 1.640s ±0.052 | 2.108s ±0.068 | 2.032s ±0.121 | 2.718s ±0.088 | 21.383s ±0.072 |
| unicode-random | 0.304s ±0.018 | 0.271s ±0.017 | 0.143s ±0.002 1 | 20.543s ±0.098 | crashed | 16.013s ±0.253 |
Alacritty and "unicode-random"
Alacritty is actually really slow at rendering this (whether it is fallback fonts in general, emojis, or something else, I don't know).
I believe the reason it finishes the benchmark so quickly is because it reads from the PTY in a separate thread, into a larger receive buffer which is then consumed by the main thread. This allows the client program to write its output much faster since it is no longer stalling on a blocked PTY.
This means Alacritty only needs to render a couple of frames since it can reach the final VT state almost immediately.
On the other hand, cat:ing the unicode-random test file in an
endless loop, or just manually scrolling up after the benchmark is
done is slow, which besides being felt (input lag), can be seen by
setting debug.render_timer = true in alacritty.yml.