Excessive script overhead #39
Description
Consider:
# grep . *.rs
h1.rs:fn main() { println!("hi") }
h2.rs:#! /usr/bin/env cargo-eval
h2.rs:fn main() { println!("hi") }
h3.rs:#! /usr/bin/env rust-script
h3.rs:fn main() { println!("hi") }
# rustc h1.rs
# hyperfine --warmup=1 ./h1 ./h2.rs ./h3.rs
Benchmark 1: ./h1
Time (mean ± σ): 1.2 ms ± 0.1 ms [User: 0.4 ms, System: 0.9 ms]
Range (min … max): 0.0 ms … 1.8 ms 1013 runs
Benchmark 2: ./h2.rs
Time (mean ± σ): 5.8 ms ± 6.9 ms [User: 2.1 ms, System: 2.7 ms]
Range (min … max): 1.4 ms … 88.8 ms 402 runs
Benchmark 3: ./h3.rs
Time (mean ± σ): 99.5 ms ± 3.8 ms [User: 84.2 ms, System: 14.0 ms]
Range (min … max): 95.8 ms … 114.0 ms 25 runs
Summary
'./h1' ran
4.95 ± 5.87 times faster than './h2.rs'
84.60 ± 10.38 times faster than './h3.rs'
On a good laptop the difference isn't so bad, ./h1 is only 30x faster than ./h3.rs. The times are above are on a server with slow HDD disks.
I was excited to see an actively maintained Rust scripting crate, but this overhead is too much. I also worry that whatever the .json writes are for will be broken if there are many concurrent runs of the script.