From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
If the old bitmap file contains a bitmap for a given commit, then that
commit does not need help from intermediate commits in its history to
compute its final bitmap. Eject that commit from the walk and insert it
as a maximal commit in the list of commits for computing bitmaps.
This helps the repeat bitmap computation task, even if the selected
commits shift drastically. This helps when a previously-bitmapped commit
exists in the first-parent history of a newly-selected commit. Since we
stop the walk at these commits and we use a first-parent walk, it is
harder to walk "around" these bitmapped commits. It's not impossible,
but we can greatly reduce the computation time for many selected
commits.
| runtime (sec) | peak heap (GB) |
| | |
| from | with | from | with |
| scratch | existing | scratch | existing |
-----------+---------+----------+---------+-----------
last patch | 100.641 | 35.560 | 2.152 | 2.224 |
this patch | 99.720 | 11.696 | 2.152 | 2.217 |
Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
---
pack-bitmap-write.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index b0493d971d..3ac90ae410 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -195,7 +195,8 @@ struct bitmap_builder {
};
static void bitmap_builder_init(struct bitmap_builder *bb,
- struct bitmap_writer *writer)
+ struct bitmap_writer *writer,
+ struct bitmap_index *old_bitmap)
{
struct rev_info revs;
struct commit *commit;
@@ -234,12 +235,26 @@ static void bitmap_builder_init(struct bitmap_builder *bb,
c_ent = bb_data_at(&bb->data, commit);
+ if (old_bitmap && bitmap_for_commit(old_bitmap, commit)) {
+ /*
+ * This commit has an existing bitmap, so we can
+ * get its bits immediately without an object
+ * walk. There is no need to continue walking
+ * beyond this commit.
+ */
+ c_ent->maximal = 1;
+ p = NULL;
+ }
+
if (c_ent->maximal) {
num_maximal++;
ALLOC_GROW(bb->commits, bb->commits_nr + 1, bb->commits_alloc);
bb->commits[bb->commits_nr++] = commit;
}
+ if (!c_ent->commit_mask)
+ continue;
+
if (p) {
struct bb_commit *p_ent = bb_data_at(&bb->data, p->item);
int c_not_p, p_not_c;
@@ -422,7 +437,7 @@ void bitmap_writer_build(struct packing_data *to_pack)
else
mapping = NULL;
- bitmap_builder_init(&bb, &writer);
+ bitmap_builder_init(&bb, &writer, old_bitmap);
for (i = bb.commits_nr; i > 0; i--) {
struct commit *commit = bb.commits[i-1];
struct bb_commit *ent = bb_data_at(&bb.data, commit);
--
2.29.2.312.gabc4d358d8
