OXYGENHUB

Benchmarks: the Linux store in change format 3 36695c5e02ef

The Linux tip's store is 324 MB after gc (objects 306 MB; Git's 311 MB)
and its first commit takes 32.6 s (Git 33.7 to 37.9 s). Backlog 3: P1
and S1 done.

closes #40
Author
Andy McCall @andymccall <[email protected]>
When
· 2026-09-30 02:56 UTC
Signature
✔ signed by Andy McCall
Hash
36695c5e02efe40e62f8fdc51e445000e2ea01664a9bafef468229d395343bf2
Depends on
1681323d1dff 1d360c91a289 33e77a5526fa b493d993a9df da652d6392d8
Depended on by
2517abe64654
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## Speed

    

  
    

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- [ ] S1 **First commit at most 50 s** (55.3 s now): profile with

    

  
    

      
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- [x] S1 **First commit at most 50 s** (55.3 s now): profile with

    

  
    

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  `perf`, and parallelise reading, hashing and diffing across the four

    

  
    

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  cores where it is safe.

    

  
    

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- [ ] S2 **Status, diff and commit** with one and with 1 000 files

    

  
    

      
      
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## Space

    

  
    

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- [ ] P1 **Store at most 350 MB after gc** (442 MB now against Git's

    

  
    

      
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- [x] P1 **Store at most 350 MB after gc** (442 MB now against Git's

    

  
    

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  311 MB): measure what takes the space (changes, text blobs, graphs,

    

  
    

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  checkpoints, indexes), then fix the largest. Compression level and

    

  
    

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  dictionary, and packing order, are all candidates.

    

  
    

      
      
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  - The vscode slice now verifies: all 1 747 commits and 3.3 million files.

    

  
    

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  - `oxy git verify` is cached by graph key and blob: 115 s instead of 1 400 s.

    

  
    

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- 2026-09-30 **H2, first part**: an import builds graphs only for the files a commit may change, from history-only states. The first 5 000 vscode commits: 309 s and 2.3 GB (from 412 s and 6.3 GB), and all verified. Next: verify and import reuse each commit's history instead of loading it again, before H3 to H5.

    

  
    

      
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- 2026-09-30 **P1 and S1 done** (oxygen#40).

    

  
    

      
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  - **Repack**: `oxy gc` repacks everything into one pack at zstd level 9, compressing on every core (9f7585d4).

    

  
    

      
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  - **Format 3**: text blobs hold the lines' bytes, with no CBOR framing (1122dcb3). The runner (oxygenflow#16) and hub (oxygenhub#59) were deployed with the new reader first.

    

  
    

      
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  - **Linux tip**: the store is 324 MB after gc (objects 306 MB; Git 311 MB). The first commit takes 32.6 s (Git 33.7 to 37.9 s), measured while Earth ran at load average 11 during the vscode import.

    

  
    

      
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  - **H2**: the vscode import (H4) runs on Earth as a service.

    

  
    

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`oxy gc` now repacks everything into one pack at zstd level 9, compressed

    

  
    

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on every core: 357 MB (349 MB pack) in 52 s. The text blob framing is the

    

  
    

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next step (a change format version 3 with raw text blobs).

    

  
    

      
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on every core: 357 MB (349 MB pack) in 52 s. Change format 3 then stores

    

  
    

      
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a text blob as the lines' bytes:

    

  
    

      
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| Linux tip | Store after gc | First commit |

    

  
    

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

    

  
    

      
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| Format 2, gc at level 3 | 390 MB | 41 s |

    

  
    

      
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| Format 2, gc repacks at level 9 | 357 MB | |

    

  
    

      
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| Format 3 (Earth at load average 11) | 324 MB (objects 306 MB) | 32.6 s, 4.4 GB |

    

  
    

      
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| Git | 311 MB (.git) | 33.7 to 37.9 s, 42 MB |

    

  
    

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