Re: [PATCH 3/2] Optimize the two-way merge of git-read-tree too
- From
Linus Torvalds <torvalds@linux-foundation.org>
- Date
- Aug 10, 2007, 19:53 UTC
- Message-ID
- <alpine.LFD.0.999.0708101240200.30176@woody.linux-foundation.org>
- In-Reply-To
- <alpine.LFD.0.999.0708101224110.30176@woody.linux-foundation.org>
On Fri, 10 Aug 2007, Linus Torvalds wrote:
> > This trivially optimizes the two-way merge case of git-read-tree too, > which affects switching branches.
Side note, if this wasn't obvious: this series of three patches (four, if you count the one in this email) obviates the need for Junio's hacky fix from yesterday that removed the "-i -m" flags from "git read-tree" in git-commit.sh, and made builtin-read-tree sometimes use the "read_tree()" function.
Now "unpack_trees()" is just fast enough that we don't need to avoid it (although it's probably still a good idea to eventually convert it to use the traverse_trees() infrastructure some day - just to avoid having extraneous tree traversal functions).
And as mentioned, the three-way case *should* be as trivial as the following. It passes all the tests, and I verified that a conflicting merge in the 100,000 file horror-case merged correctly (with the conflict markers) in 0.687 seconds with this, so it works, but I'm lazy and somebody else should double-check it.
(Again - *without* this patch, the merge took 8.355 seconds, so this patch really does make a huge difference for merge performance with lots and lots of files, and we're not talking percentages, we're talking orders-of-magnitude differences!)
Linus
--- unpack-trees.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/unpack-trees.c b/unpack-trees.c index 810816e..ccfeb6e 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -667,7 +667,6 @@ int threeway_merge(struct cache_entry **stages, int no_anc_exists = 1; int i; - remove_entry(remove); for (i = 1; i < o->head_idx; i++) { if (!stages[i] || stages[i] == o->df_conflict_entry) any_anc_missing = 1; @@ -730,8 +729,10 @@ int threeway_merge(struct cache_entry **stages, } /* #1 */ - if (!head && !remote && any_anc_missing) + if (!head && !remote && any_anc_missing) { + remove_entry(remove); return 0; + } /* Under the new "aggressive" rule, we resolve mostly trivial * cases that we historically had git-merge-one-file resolve. @@ -763,6 +764,7 @@ int threeway_merge(struct cache_entry **stages, if ((head_deleted && remote_deleted) || (head_deleted && remote && remote_match) || (remote_deleted && head && head_match)) { + remove_entry(remove); if (index) return deleted_entry(index, index, o); else if (ce && !head_deleted) @@ -785,6 +787,7 @@ int threeway_merge(struct cache_entry **stages, verify_uptodate(index, o); } + remove_entry(remove); o->nontrivial_merge = 1; /* #2, #3, #4, #6, #7, #9, #10, #11. */