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
argp	derive	Added in this fork
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	475ms (full) 328ms (incremental)	1ms	Y	-	-
argp	44 KiB	8s (full) 436ms (incremental)	1ms	Y		v0.3.0
argh	24 KiB	6s (full) 420ms (incremental)	1ms	N		v0.1.10
bpaf	124 KiB	2s (full) 469ms (incremental)	2ms	Y		v0.7.10
bpaf_derive	124 KiB	8s (full) 457ms (incremental)	2ms	Y		v0.7.10
clap	348 KiB	7s (full) 746ms (incremental)	2ms	Y		v4.2.0
clap-minimal	220 KiB	4s (full) 595ms (incremental)	2ms	Y		v4.2.0
clap_derive	364 KiB	12s (full) 828ms (incremental)	2ms	Y		v4.2.0
clap_lex	16 KiB	785ms (full) 394ms (incremental)	1ms	Y		v0.4.1
gumdrop	20 KiB	6s (full) 422ms (incremental)	1ms	N		v0.8.1
lexopt	20 KiB	755ms (full) 354ms (incremental)	1ms	Y		v0.3.0
pico-args	16 KiB	732ms (full) 363ms (incremental)	6ms	Y		v0.5.0
xflags	16 KiB	1s (full) 350ms (incremental)	1ms	Y		v0.3.1

System: Linux 5.15.0-1034-azure (x86_64) w/ -j 2 (GitHub actions, see log)

rustc: rustc 1.68.2 (9eb3afe9e 2023-03-27)

Notes:

• Overhead will be lower if your application shares dependencies with your argument parsing library.
• Size is measured on release builds with panic = "abort" and strip = true.

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