git import at depth: merges take 85% of the time issue #80 closed: completed andymccall opened this 29 days ago · 0 comments

Measured on a recovered copy of the VS Code import at 118k commits (oxygen#79), 400 commits with OXY_IMPORT_STOP_AFTER and per-commit times in the trace: 24 merges took 946 s of 1117 s (avg 42 s, max 160 s for a merge bringing 593 commits); 376 ordinary commits averaged 361 ms. Render base is 1052 s: whole-tree render 682 s, 'same and need' 252 s (a full tree view built every commit), materialize 113 s; bases rebuilt only 6 times (48 s). Next: per-merge need sizes and where the whole-tree time goes, then render only what a merge needs; cache the tree view between commits.