Re: [PATCH 09/16] documentation: add documentation for the bitmap format

Right, the format and implementation in JGit can do Counting objects in 87ms for the Linux kernel history. Actually, that was the timing when I first pushed the change. With the improvements submitted throughout the year, we can do counting in 50ms, on my same machine. But I think we are

Re: [PATCH 09/16] documentation: add documentation for the bitmap format

Pinning the bitmap index on the reverse index adds complexity (lookups are two-step: first find the entry in the reverse index, and then find the SHA1 in the index) and is measurably slower, in both loading and lookup times. Since Git doesn't have a memory problem, it's very hard to make an

Re: [PATCH 09/16] documentation: add documentation for the bitmap format

Pinning the bitmap index on the reverse index adds complexity (lookups are two-step: first find the entry in the reverse index, and then find the SHA1 in the index) and is measurably slower, in both loading and lookup times. Since Git doesn't have a memory problem, it's very hard to make an

Re: [PATCH 09/16] documentation: add documentation for the bitmap format

+ Generating this reverse index at runtime is **not** free (around 900ms + generation time for a repository like `torvalds/linux`), and once again, + this generation time needs to happen every time `pack-objects` is + spawned. If generating the reverse index is expensive, it is probably