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docs: update README benchmarks with fresh 7840U numbers and emoji indicators

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Replace all N100 benchmark data with accurate 7840U results. Add emoji
legend (winner/loser/tie) to every comparison row. Update crate property
table, machine description, and recommendation prose to reflect current
competitive picture.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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swaitsandClaude Opus 4.6 committed 2026-03-31 16:30:05 -06:00
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@@ -26,88 +26,93 @@ Benchmarked against the two other `no_std` COBS crates using
[Criterion](https://github.com/bheisler/criterion.rs) across three payload
patterns: **all zeros** (worst case — every byte triggers a code emit),
**no zeros**, and **mixed** (0x00–0xFF cycling). Throughput in MB/s, higher
is better.
is better. Legend: 🥇 winner, 🥉 last, 🤝 statistical tie (<5%).
### Encode
| Payload | Pattern | μCOBS | `cobs` 0.3 | `corncobs` 0.1 |
| Payload | Pattern | μCOBS | `cobs` 0.5 | `corncobs` 0.1 |
|---------|---------|------:|-----------:|---------------:|
| 64 B | zeros | 595 | 748 | 180 |
| 64 B | mixed | 1,853 | 1,011 | 1,734 |
| 64 B | nonzero | 1,884 | 1,012 | 2,110 |
| 256 B | zeros | 654 | 817 | 184 |
| 256 B | mixed | 1,888 | 1,002 | 1,887 |
| 256 B | nonzero | 1,964 | 1,004 | 1,968 |
| 4096 B | zeros | 675 | 845 | 188 |
| 4096 B | mixed | 1,734 | 1,016 | 1,746 |
| 4096 B | nonzero | 1,775 | 1,020 | 2,245 |
| 64 B | zeros | 1,485 | 🥇 1,572 | 🥉 274 |
| 64 B | nonzero | 🤝 3,721 | 🥉 2,177 | 🤝 3,616 |
| 64 B | mixed | 🥇 3,596 | 🥉 2,019 | 3,137 |
| 256 B | zeros | 1,494 | 🥇 1,962 | 🥉 341 |
| 256 B | nonzero | 🥇 4,267 | 🥉 2,218 | 3,951 |
| 256 B | mixed | 🤝 3,891 | 🥉 2,114 | 🤝 3,867 |
| 4096 B | zeros | 1,376 | 🥇 2,052 | 🥉 334 |
| 4096 B | nonzero | 🤝 4,538 | 🥉 2,227 | 🤝 4,501 |
| 4096 B | mixed | 🤝 3,993 | 🥉 1,549 | 🤝 3,888 |
### Decode
| Payload | Pattern | μCOBS | `cobs` 0.3 | `corncobs` 0.1 |
| Payload | Pattern | μCOBS | `cobs` 0.5 | `corncobs` 0.1 |
|---------|---------|------:|-----------:|---------------:|
| 64 B | zeros | 595 | 440 | 732 |
| 64 B | mixed | 7,041 | 504 | 7,991 |
| 64 B | nonzero | 9,900 | 502 | 9,807 |
| 256 B | zeros | 656 | 472 | 742 |
| 256 B | mixed |17,024 | 645 | 16,207 |
| 256 B | nonzero |18,456 | 647 | 19,549 |
| 4096 B | zeros | 675 | 483 | 768 |
| 4096 B | mixed |17,522 | 656 | 22,959 |
| 4096 B | nonzero |37,987 | 623 | 40,005 |
| 64 B | zeros | 🥇 2,896 | 🥉 924 | 1,520 |
| 64 B | nonzero | 🤝 16,000 | 🥉 1,168 | 🤝 15,238 |
| 64 B | mixed | 9,275 | 🥉 1,133 | 🥇 15,610 |
| 256 B | zeros | 🥇 3,088 | 🥉 914 | 1,496 |
| 256 B | nonzero | 40,000 | 🥉 1,179 | 🥇 42,667 |
| 256 B | mixed | 28,444 | 🥉 1,140 | 🥇 37,647 |
| 4096 B | zeros | 🥇 4,620 | 🥉 942 | 1,549 |
| 4096 B | nonzero | 🥇 68,040 | 🥉 1,203 | 58,851 |
| 4096 B | mixed | 40,236 | 🥉 1,154 | 🥇 49,769 |
### Code size
Measured from `.text` section of release-optimized symbols (`encode` + `decode`
combined):
| Crate | Code size |
|----------------|----------:|
| μCOBS | 541 B |
| `cobs` 0.3 | 537 B |
| `corncobs` 0.1 | 637 B |
| Crate | `encode` | `decode` | Total |
|----------------|--------:|---------:|------:|
| μCOBS | 434 B | 435 B | 869 B |
| `cobs` 0.5 | 245 B | 292 B | 537 B |
| `corncobs` 0.1 | 375 B | 262 B | 637 B |
All three crates are tiny. The difference is negligible for any target.
All three crates are under 1 KB. μCOBS is the largest due to its
optimized encode (sub-slice scan, zero fast path, `copy_from_slice`)
and decode (batch zero fill) paths.
### Crate properties
| Property | μCOBS | `cobs` 0.3 | `corncobs` 0.1 |
| Property | μCOBS | `cobs` 0.5 | `corncobs` 0.1 |
|----------------|:------:|:-----------------:|:--------------:|
| `no_std` | always | opt-in[^1] | always |
| Zero-alloc | yes | opt-in[^2] | yes |
| `unsafe`-free | yes | yes | yes |
| `const fn` encode | yes | no | no |
| Implementation | ~120 LOC | ~790 LOC | ~645 LOC |
| Implementation | ~140 LOC | ~790 LOC | ~645 LOC |
[^1]: Requires disabling the default `std` feature.
[^2]: `alloc` is enabled by default via the `std` feature.
> Measured on Intel N100, Rust 1.93.1, Linux 6.12. Run `just bench` to
> reproduce. Full Criterion reports are generated in `target/criterion/report/`.
> Measured on AMD Ryzen 7 7840U, Rust 1.93.1, Linux 6.18. Run `just bench`
> to reproduce. Full Criterion reports are generated in `target/criterion/report/`.
## When to use μCOBS
| You need… | μCOBS | `cobs` 0.3 | `corncobs` 0.1 |
| You need… | μCOBS | `cobs` 0.5 | `corncobs` 0.1 |
|---|:---:|:---:|:---:|
| Minimal code to audit | **~120 LOC** | ~790 LOC | ~645 LOC |
| Minimal code to audit | **~140 LOC** | ~790 LOC | ~645 LOC |
| Compile-time (`const fn`) encode | **yes** | no | no |
| Fastest encode (zero-heavy data) | **3–4×** faster | baseline | slowest |
| Fastest decode (large payloads) | competitive | slow | **slight edge** |
| Fastest encode (nonzero/mixed) | **yes** | no | ties μCOBS |
| Fastest encode (zero-heavy) | 2nd | **yes** | no |
| Fastest decode (zero-heavy) | **yes (3×)** | no | 2nd |
| Fastest decode (nonzero) | **ties corncobs** | no | **ties μCOBS** |
| Fastest decode (mixed) | 2nd | no | **yes** |
| Dead-simple API (3 functions) | **yes** | yes | more surface area |
| In-place / streaming encode | no | no | **yes** |
| `no_std` + zero-alloc by default | **yes** | opt-in | **yes** |
| Thorough test suite | **106 tests, fuzz, proptest** | basic | basic |
**Choose μCOBS** if you want the smallest, most auditable COBS implementation
with a minimal API and strong performance — especially on embedded targets or
payloads containing many zero bytes.
with a `const fn` encoder, a dead-simple 3-function API, and leading or
competitive throughput across most workloads — especially on embedded targets.
**Choose `corncobs`** if you need in-place encoding, an iterator-based API, or
your workload is dominated by large non-zero payloads where it holds a slight
throughput edge.
**Choose `corncobs`** if you need in-place encoding, an iterator-based API,
or your workload is dominated by large mixed-pattern decoding where it holds
a throughput edge.
**Choose `cobs`** if you need `std` convenience features and don't care about
`no_std` or encode performance.
**Choose `cobs`** if you need `std` convenience features, a streaming state
machine, or your data is predominantly zero-heavy where it leads on encode.
## Examples