btop might be measuring the wrong thing here, but alacritty on my box shows 93M using the same interface. I remember benchmarking foot and alacritty (also kitty) pretty extensively a few years ago, and settled on foot.
Though of course, the memory usage on modern machines is really not a major issue, but the configuration update, along with the tmux session death was annoying..
EDIT: Some timing metrics..
foot -s &
hyperfine --warmup 8 'alacritty -e true' 'foot -e true' 'footclient -e true'
Benchmark 1: alacritty -e true
Time (mean ± σ): 99.0 ms ± 14.2 ms [User: 58.5 ms, System: 33.4 ms]
Range (min … max): 82.7 ms … 148.3 ms 32 runs
Benchmark 2: foot -e true
Time (mean ± σ): 37.2 ms ± 2.3 ms [User: 40.3 ms, System: 9.5 ms]
Range (min … max): 33.8 ms … 43.7 ms 83 runs
Benchmark 3: footclient -e true
Time (mean ± σ): 22.8 ms ± 4.3 ms [User: 0.9 ms, System: 0.8 ms]
Range (min … max): 18.2 ms … 63.6 ms 133 runs
Summary
footclient -e true ran
1.63 ± 0.32 times faster than foot -e true
4.35 ± 1.03 times faster than alacritty -e true
timing footclient -e true is not actually measuring what you think its measuring. It's measuring the time it takes to open a socket and write a few bytes to it. Not the time it takes to run true in a new window and then close it. And just FYI both alacritty and kitty have server/client modes too. foot without server client mode does indeed startup faster than any GPU based terminal emulator because GPU based terminal emulators have to probe the GPU card(s) ont he system for their capabilities which is approx 100ms of unavoidable delay until someone convinces the kernel developers to cache this data.
In client server mode all of foot/alacritty/kitty/urxvt will open windows in a few ms.
Though of course, the memory usage on modern machines is really not a major issue, but the configuration update, along with the tmux session death was annoying..
EDIT: Some timing metrics..