Busybox wc is back in every suite, for shits and giggles. checkwc now walks PATH and identifies each wc by its --version answer (coreutils and fastwc respond; busybox names itself in the error it prints), so a wc symlinked to fastwc is detected and skipped instead of silently racing us against ourselves, and a missing coreutils is a clear configure error. Every run now ends with the average speedup of fastwc against coreutils and busybox, computed from the per-case ratios. The fail-fast verdict now requires a measurable (>0ms) reference time, so sub-millisecond cases stop flaking on startup noise, and the 100M line monster is pinned back to the coreutils oracle instead of whatever oracle was raced last.
fastwc
The word counter GNU wishes it could be.
GNU coreutils wc is the Apple of the FOSS world. Forty years of
accumulated bureaucracy wrapped in a binary. Translation teams. gettext.
--help output in fourteen languages. An autotools contraption the size
of a small city, all so you can count newlines. And when it can't keep
up, it doesn't get faster — it gets more dependencies.
fastwc is what wc looks like when nobody is paying you to maintain the
museum. One file. One purpose. No translators. No gnulib. No AVX-512
kernels hand-tuned by people whose entire job is compensating for the
bloat around them — just our own: AVX-512, AVX-2, and SSE2 intrinsics
with runtime dispatch, and a scalar SWAR fallback. Just counting,
correctly, at full speed.
The scoreboard
The benchmark suite in benchmarks/ races fastwc against GNU wc —
fail-fast. The moment we are slower, or disagree on a single count, it
writes a shame report and exits non-zero. These are the facts:
| Suite | Result |
|---|---|
| words (6 cases) | 6/6 wins. Never slower, never wrong. |
| lines (up to 100k lines) | Wins. GNU never sees us coming. |
| lines (1M lines) | Win: 1ms vs 2ms. GNU's AVX-512 assist can't beat a mapped file. |
| lines (10M lines) | Win: 8-9ms vs 22-24ms (~2.5x). GNU's lead never survives contact with the buffer. |
| lines (100M lines) | Win: ~70ms vs ~140ms. The monster race. GNU gets lapped. |
| lines (1B lines) | Solo, ~4-6s. 11 GB in one pass; the only bottleneck left is the disk. |
| stdin words (1M lines) | Win: 12x. GNU still reads stdin like it's 1985. |
| stdin lines (10M lines) | Win: ~2.5x. We map stdin redirects; GNU maps nothing. |
The moment fastwc is slower than GNU wc, this project has failed and
you should say so loudly in an issue. The benchmark is the contract.
The how and why of the speed, with receipts, lives in
docs/PERFORMANCE.md.
GNU wc's lone win — 1M lines, by a single millisecond, on hand-tuned AVX-512 assembly — is a historical footnote now. We closed it, then the 10M case, then the 100M monster, and then we added a 1B-line race with no opponent, because beating GNU wc at this point is just cruelty to software. Busybox is back in the suite too — for shits and giggles. It stopped being a challenge years ago, but watching it count is the closest thing this project has to a hobby. Every run ends with the average speedup against each oracle, so the cruelty is quantified.
Why
- GNU wc is a dependency museum. Its build needs gettext, gnulib,
and a translator for every language on Earth. fastwc needs
cc. - GNU wc is slow where it should be fast. Counting bytes is not supposed to be an architectural achievement. Counting 11 GB of them in one pass, solo, while GNU's AVX-512 assembly still needs a buffer to copy into — that is.
- GNU wc counts like it's 1985 — because it is. We count like it's now: regular files are mapped and counted in parallel across cores, with SIMD kernels (AVX-512, AVX-2, SSE2) dispatched at runtime — zero function calls in the hot path.
What it does
fastwc [OPTION]... [FILE]...
fastwc [OPTION]... --files0-from=F
-llines,-wwords,-cbytes,-mcharacters (multibyte),-Lmaximum line length (display width, tab stops every 8)--files0-from=FNUL-terminated file lists from F (or stdin when F is-)--total=auto|always|only|nevercontrol over the total row--debugreport which line-counting acceleration is in use- stdin,
-, multiple files,totalrows, GNU-compatible counts - A CLI surface modeled on GNU coreutils
wc9.11: same options, same column alignment rule (counts are right-justified to the widest sum of regular file sizes), same multibyte word semantics, same error text. Swap it in and scripts keep working. - POSIXLY_CORRECT is honored: the no-break space stops being a word separator, exactly like GNU wc.
- no
--helpin fourteen languages. One--help, in English, the language of people who ship software
Build
Requires a C compiler and autotools. That's it. No gettext. No gnulib. No translators.
./autogen.sh # autoreconf -fi && ./configure
make
make release # installs the release binary to bin/release/fastwc
Benchmark
make bench # build release + run every suite
./benchmarks/test-all.sh # all suites: words, lines, stdin
The suites live under benchmarks/files/{lines,words} (file input) and
benchmarks/stdin/piping (standard input), and fail fast the moment
fastwc loses a single case. Every suite races against GNU coreutils wc
and, when it is installed, busybox wc. The benchmark locates the real
oracles by their --version answer — a wc that answers as fastwc is a
symlink somebody made, and is skipped rather than raced against itself.
The lines suite also carries the monsters: 100M lines raced against
coreutils, and 1B lines timed solo — there is no reference for that
one; we are the reference now. The suites interleave runs so both
commands see identical cache warmth, keep the minimum, and fail the
moment fastwc loses a single case. When the run ends, the average
speedup of fastwc against each oracle is printed.
Development
The editor setup is one command:
make compile-commands # compile_commands.json for clangd
clangd reads .clangd, .clang-tidy, and .clang-format — the style
guide, enforced by robots. We use bear when it's installed; the
fallback hand-rolls the single entry from the Makefile, because one
source file doesn't need a database.
make format— make the code confess to the style guidemake format-check— verify without touchingmake lint— clang-tidy, static analysis included
.editorconfig and .gitattributes keep every editor honest. Your
editor has opinions. So do we. Ours are in the repo.
License
MIT. Do whatever you want. We're not GNU, we won't sue you — we'll just be faster.
Contributing
See CONTRIBUTING.md — the rules are the deal. See STYLEGUIDE.md — the style is the law.