Rust String Parsing Benchmarks
This repo tries to assess Rust string types.
We currently compare:
| Name | Heap | Inline | &'static str |
Mutable | Unsafe | Notes |
|---|---|---|---|---|---|---|
String |
Y | - | N | Y | - | Universal |
Cow<'static, str> |
Y | - | Y | N | - | |
compact_str |
Y | 24 bytes | N | Y | Y (miri, proptest, fuzz) | |
flexstr |
Y | 22 bytes | Y | N | Y (miri) | O(1) clone |
kstring |
Y | 15 bytes | Y | N | Optional (miri, proptest) | Optional O(1) clone, optional 22 byte small string, Ref/Cow API for preserving &'static str |
smartstring |
Y | 23 bytes | N | Y | Y (miri, proptest, fuzz) | |
smol_str |
Y | 22 bytes | N | N | Y (miri, proptest) | O(1) clone, Whitespace storage optimizations |
Suggestions:
- Generally,
String - If you deal mostly with string literals but want some flexibility (like
clap), generally you'll want
Cow<'static, str> - If a profiler says your strings are a problem:
- Try different crates and settings for that crate out with a profiler
- O(1) clones are important when doing a lot of clones. For one-off allocations, they are slower.
- For short-lived programs, look into string interning
Terms:
- Heap: will store strings in heap-allocated memory
- Inline: will store small-enough strings on the stack
Results
new summary:
See more details
clone summary:
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access summary:
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Special Thanks
- djc for inspiration with template-benchmarks-rs