On Thu, Nov 03, 2022 at 03:37:25PM +0100, Patrick Steinhardt wrote: > Overall the performance improvement isn't quite as strong as before: > we're only 4.5x faster compared to 6.5x in our repo. But I guess that's > still a good-enough improvement, doubly so that there are no downsides > for repos anymore that ain't got any hidden refs. Just a guess, but the extra time is probably spent because "rev-list" has to iterate over your kajillion refs saying "nope, not this one". I wonder if there is a way to carve up the ref namespace early, in a trie-like way, similar to how for_each_fullref_in_prefixes() skips straight to the interesting part. It's a harder problem, because we are excluding rather than including entries based on our patterns. But it seems like you'd be able to notice that we are on "refs/foo/bar", that all of "refs/foo" is excluded, and jump ahead to the end of the "refs/foo" section by binary-searching for the end within the packed-refs file. And that would speed up both this rev-list, but also the initial advertisement that receive-pack does, because it's also iterating all of these saying "nope, it's hidden". And assuming these are all internal refs you hide from users, upload-pack would benefit, too. I don't think that should be part of this series, but it may be an interesting future direction. -Peff
