Hi Victoria
On 10/11/2022 01:57, Victoria Dye via GitGitGadget wrote:
From: Victoria Dye <vdye@xxxxxxxxxx>
Enable the 'skip_cache_tree_update' option in both 'do_reset()'
('sequencer.c') and 'reset_head()' ('reset.c'). Both of these callers invoke
'prime_cache_tree()' after 'unpack_trees()', so we can remove an unnecessary
cache tree rebuild by skipping 'cache_tree_update()'.
When testing with 'p3400-rebase.sh' and 'p3404-rebase-interactive.sh', the
performance change of this update was negligible, likely due to the
operation being dominated by more expensive operations (like checking out
trees).
Yes, we only call this once at the beginning of the rebase and then for
any reset commands and the run time will be dominated by picking commits.
However, since the change doesn't harm performance, it's worth
keeping this 'unpack_trees()' usage consistent with others that subsequently
invoke 'prime_cache_tree()'.
That makes sense
Signed-off-by: Victoria Dye <vdye@xxxxxxxxxx>
---
reset.c | 1 +
sequencer.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/reset.c b/reset.c
index e3383a93343..5ded23611f3 100644
--- a/reset.c
+++ b/reset.c
@@ -128,6 +128,7 @@ int reset_head(struct repository *r, const struct reset_head_opts *opts)
unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
unpack_tree_opts.update = 1;
unpack_tree_opts.merge = 1;
unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
+ unpack_tree_opts.skip_cache_tree_update = 1;
I've added an extra context line above to show that we do either a
one-way or two-way merge - is it safe to skip the cache_tree_update for
the two-way merge? (I'm afraid I seem to have forgotten everything I
learnt about prime_cache_tree() and cache_tree_update() when we
discussed this optimization before).
Best Wishes
Phillip
init_checkout_metadata(&unpack_tree_opts.meta, switch_to_branch, oid, NULL);
if (reset_hard)
unpack_tree_opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;
diff --git a/sequencer.c b/sequencer.c
index e658df7e8ff..3f7a73ce4e1 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -3750,6 +3750,7 @@ static int do_reset(struct repository *r,
unpack_tree_opts.merge = 1;
unpack_tree_opts.update = 1;
unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
+ unpack_tree_opts.skip_cache_tree_update = 1;
init_checkout_metadata(&unpack_tree_opts.meta, name, &oid, NULL);
if (repo_read_index_unmerged(r)) {
