[RFC PATCH v2 9/9] diffcore-rename: filter rename_src list when possible
- From
Elijah Newren <newren@gmail.com>
- Date
- Nov 20, 2017, 22:19 UTC
- Message-ID
- <20171120221944.15431-10-newren@gmail.com>
- In-Reply-To
- <20171120221944.15431-1-newren@gmail.com>
We have to look at each entry in rename_src a total of rename_dst_nr times. When we're not detecting copies, any exact renames or ignorable rename paths will just be skipped over. While checking that these can be skipped over is a relatively cheap check, it's still a waste of time to do that check more than once, let alone rename_dst_nr times. When rename_src_nr is a few thousand times bigger than the number of relevant sources (such as when cherry-picking a commit that only touched a handful of files, but from a side of history that has different names for some high level directories), this time can add up.
First make an initial pass over the rename_src array and move all the relevant entries to the front, so that we can iterate over just those relevant entries.
In one particular testcase involving a large repository and some high-level directories having been renamed, this cut the time necessary for a cherry-pick down by a factor of about 2 (from around 34 seconds down to just under 16 seconds)
Signed-off-by: Elijah Newren <newren@gmail.com> --- diffcore-rename.c | 47 +++++++++++++++++++++++++++++++---------------- 1 file changed, 31 insertions(+), 16 deletions(-)
diff --git a/diffcore-rename.c b/diffcore-rename.c index 5bf5bf7379..e60abb5980 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -437,16 +437,14 @@ static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, i return count; } -static int handle_rename_ignores(struct diff_options *options) +static void handle_rename_ignores(struct diff_options *options) { - int detect_rename = options->detect_rename; struct string_list *ignores = options->ignore_for_renames; - int ignored = 0; int i, j; /* rename_ignores onlhy relevant when we're not detecting copies */ - if (ignores == NULL || detect_rename == DIFF_DETECT_COPY) - return 0; + if (ignores == NULL) + return; for (i = 0, j = 0; i < ignores->nr && j < rename_src_nr;) { struct diff_filespec *one = rename_src[j].p->one; @@ -464,11 +462,27 @@ static int handle_rename_ignores(struct diff_options *options) j++; else { one->rename_used++; - ignored++; + i++; + j++; } } +} + +static int remove_renames_from_src(void) +{ + int j, new_j; + + for (j = 0, new_j = 0; j < rename_src_nr; j++) { + if (rename_src[j].p->one->rename_used) + continue; + + if (new_j < j) + memcpy(&rename_src[new_j], &rename_src[j], + sizeof(struct diff_rename_src)); + new_j++; + } - return ignored; + return new_j; } void diffcore_rename(struct diff_options *options) @@ -479,7 +493,7 @@ void diffcore_rename(struct diff_options *options) struct diff_queue_struct outq; struct diff_score *mx; int i, j, rename_count, skip_unmodified = 0; - int num_create, dst_cnt, num_src, ignore_count; + int num_create, dst_cnt, num_src; struct progress *progress = NULL; if (!minimum_score) @@ -542,18 +556,19 @@ void diffcore_rename(struct diff_options *options) /* * Mark source files as used if they are found in the - * ignore_for_renames list. + * ignore_for_renames list, and clean out files from rename_src + * that we don't need to continue considering. */ - ignore_count = handle_rename_ignores(options); + num_src = rename_src_nr; + if (detect_rename != DIFF_DETECT_COPY) { + handle_rename_ignores(options); + num_src = remove_renames_from_src(); + } /* - * Calculate how many renames are left (but all the source - * files still remain as options for rename/copies!) + * Calculate how many renames are left */ num_create = (rename_dst_nr - rename_count); - num_src = (detect_rename == DIFF_DETECT_COPY ? - rename_src_nr : rename_src_nr - rename_count); - num_src -= ignore_count; /* All done? */ if (!num_create) @@ -588,7 +603,7 @@ void diffcore_rename(struct diff_options *options) for (j = 0; j < NUM_CANDIDATE_PER_DST; j++) m[j].dst = -1; - for (j = 0; j < rename_src_nr; j++) { + for (j = 0; j < num_src; j++) { struct diff_filespec *one = rename_src[j].p->one; struct diff_score this_src;
-- 2.15.0.323.g31fe956618