Benchmarks: S1's first round on the Linux tree (refs #41) bd9414401fdc

- 2026-09-30 **S1, first round** (commits c9dca9ed to 077e899b; table in `docs/benchmarks.md`). A lister of our own replaces the ignore crate's walker (listing 0.5 s to 0.18 s); the manifest is a flat binary file with hashes and graph keys as bytes; the state index keeps each file's history encoded until used (a writer bug I made on the way was caught only on Earth, since a failed index read falls back to a full load: test builds now read every index written back); maps are built in path order; mimalloc is the allocator. Clean status is now ahead of Git (0.18 s against 0.22 s), the first commit too (24.4 s against 36.2 s), and gc (29.9 s against 70.3 s). One-file status is 0.47 s against 0.22 s. Log (S3, first part): metadata from the state index and a store cache, signature marks without reading changes: 0.20 s, of which 9 ms is the log. For Andy: `oxy log` checks the working copy first (about 0.18 s here); Git's log does not look at it. Dropping that check would make log about 20 ms, but the working-copy line would then show the last snapshot's state.

### S1, first part: walk, manifest, lazy index, mimalloc (2026-09-30 22:39, oxygen#41)

The same script after the first round of S1: a lister of our own in place

of the ignore crate's walker, the manifest as a flat binary file with

hashes as bytes, each file's history in the state index decoded only when

used, maps built in path order, and mimalloc as the allocator. Earth's

load average was 4 to 5 (no Flow jobs); runs alternate with Git.

| Operation | oxy | before (21:43) | Git |

|---|---:|---:|---:|

| init and commit the tip | **24.4 s**, 3.2 GB | 33.3 s, 3.1 GB | 36.2 s |

| status, clean | **0.17 to 0.18 s**, 130 to 150 MB | 0.43 to 0.53 s | 0.22 to 0.23 s |

| status, one file | 0.47 s (1.47 s first) | 1.73 to 1.81 s | 0.22 to 0.23 s |

| diff, one file | 0.47 to 0.51 s | 1.77 to 2.24 s | 0.11 to 0.14 s |

| commit, one file | 0.96 s | 3.10 s | 0.17 s |

| status, 1 000 files | 0.65 s (1.99 s first) | 1.62 s | 0.23 to 0.24 s |

| diff, 1 000 files | 0.65 s | 1.54 to 2.40 s | 0.46 to 0.48 s |

| commit, 1 000 files | 1.20 s | 2.47 s | 0.50 s |

| log -n 100 | 0.48 to 0.53 s | 0.86 to 1.03 s | 0.00 s |

| blame MAINTAINERS | 0.59 s | 0.99 to 1.04 s | 0.07 s |

| clone, local path | 36.7 s, 3.6 GB | 56.3 s | 18.0 s |

| checkout the first state, and back | 1.48 s, 1.37 s | 2.86 s, 3.00 s | 0.35 s, 0.34 s |

| fsck | 14.0 s, 1.0 GB | 24.4 s | 12.6 s |

| gc | **29.9 s** | 48.1 s | 70.3 s |

| store after gc | 369 MB | 375 MB | 295 MB |

mimalloc alone took one-file status from 0.78 to 0.47 s and clean status

from 0.26 to 0.18 s: status allocates hundreds of thousands of small

values from every thread, and glibc's arena locks were the largest single

cost. The first status after a commit (1.47 s) rebuilds the state index.

Afterwards (22:55), log reads change metadata from the state index and a

metadata cache in the store, and its signature marks no longer read each

change whole: `log -n 100` takes 0.19 to 0.20 s, of which 9 ms is the log

itself and the rest the check that the working copy is clean.

Where one-file status goes now (0.47 s): listing the working copy about

150 ms (the syscalls alone: `find` with a stat of each file takes 0.37 s

on one core), loading the state index about 60 ms, reading the manifest

about 40 ms, rendering and diffing the changed file about 100 ms.