README.md

Rust Arg Parsing Benchmarks

This repo tries to assess Rust arg parsing performance.

We currently compare:

Name	Style	Notes
No-op	N/A	N/A
argh	derive
bpaf	Combinatoric or derive
clap_lex	Imperative	No help generation
clap	Builder or derive	Color, suggested fixes, completions
gumdrop	derive
lexopt	Imperative	No help generation
pico-args	Imperative	No help generation
xflags	proc-macro

See also an examination of design trade offs

Note: any non-performance comparison is meant to provide context for what you gain/lose with each crate's overhead. For a full comparison, see each parser docs

Results

Name	Overhead (release)	Build (debug)	Parse (release)	Invalid UTF-8	Downloads	Version
null	0 KiB	234ms (full) 172ms (incremental)	3ms	Y	-	-
argh	38 KiB	3s (full) 203ms (incremental)	4ms	N		v0.1.10
bpaf	282 KiB	965ms (full) 236ms (incremental)	5ms	Y		v0.9.4
bpaf_derive	276 KiB	4s (full) 238ms (incremental)	5ms	Y		v0.9.4
clap	654 KiB	3s (full) 392ms (incremental)	4ms	Y		v4.4.0
clap-minimal	427 KiB	2s (full) 330ms (incremental)	4ms	Y		v4.4.0
clap_derive	689 KiB	6s (full) 410ms (incremental)	4ms	Y		v4.4.0
clap_lex	27 KiB	407ms (full) 188ms (incremental)	3ms	Y		v0.5.1
gumdrop	37 KiB	3s (full) 198ms (incremental)	3ms	N		v0.8.1
lexopt	34 KiB	385ms (full) 184ms (incremental)	3ms	Y		v0.3.0
pico-args	23 KiB	384ms (full) 185ms (incremental)	3ms	Y		v0.5.0
xflags	22 KiB	709ms (full) 179ms (incremental)	3ms	Y		v0.3.1

System: Linux 5.4.0-124-generic (x86_64) w/ -j 8

rustc: rustc 1.72.0 (5680fa18f 2023-08-23)

Notes:

• Overhead will be lower if your application shares dependencies with your argument parsing library.

Running the Benchmarks

$ ./bench.py
$ ./format.py

To be included, the crate needs meet one of the following criteria:

• 10k+ recent downloads
• Unique API design

Special Thanks

• RazrFalcon for creating the initial benchmarks
• djc for inspiration with template-benchmarks-rs
• sharkdp for hyperfine