Add performance improvements to git-last-modified(1)
The subcommand git-last-modified(1) was based on the patches shared by Taylor and the folks at GitHub1. That version used an alternative implementation to make it "go faster". When I was working on upstreaming those patches, I dropped the patches2 for this implementation, because I didn't see significant improvements.
This series revives those changes. I did more thorough deep dive through the code and the algorithm and got the code working a lot faster. The benchmark results can be found in the commit message.
Some changes compared to GitHub's version include:
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Use of
struct bitmapfrom "ewah/ewok.h", instead of self-definedstruct commit_active_paths. -
Removed shortcut code that handled the case when commit and parent are fully treesame, and instead always checked 'active_c' whether the next parent is worth looking at.
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Modified comments and commit message to make the algorithm more clear (at least to me).
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Mentioned the use of PARENT1 and PARENT2 in object.h.
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Removed the use of any global variables.
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Less conditions are checked in mark_path() because the hashmap of 'paths' is considered the single-source of truth.
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pass_to_parent() doesn't pass on when the path isn't in the 'paths' hashmap no more.
Cc: Karthik Nayak karthik.188@gmail.com Cc: Justin Tobler jltobler@gmail.com Cc: Taylor Blau me@ttaylorr.com Signed-off-by: Toon Claes toon@iotcl.com
Changes in v2:
- EDITME: describe what is new in this series revision.
- EDITME: use bulletpoints and terse descriptions.
- Link to v1: https://lore.kernel.org/r/20251016-b4-toon-last-modified-faster-v1-1-85dca8a29e5c@iotcl.com
--- b4-submit-tracking ---
This section is used internally by b4 prep for tracking purposes.
{ "series": { "revision": 2, "change-id": "20251009-b4-toon-last-modified-faster-4c8956a95261", "prefixes": [], "history": { "v1": [ "20251016-b4-toon-last-modified-faster-v1-1-85dca8a29e5c@iotcl.com" ] } } }