This is a minor update to address Ben's comments and add his
measurements in the commit message of 2/4 for the record.
I've also checked about the lookahead thing in unpack_trees() to see
if we accidentally break something there, which is my biggest worry.
See [1] and [2] for context, but I believe since we can't have D/F
conflicts, the situation where lookahead is needed will not occur. So
we should be safe.
[1] da165f470e (unpack-trees.c: prepare for looking ahead in the index - 2010-01-07)
[2] 730f72840c (unpack-trees.c: look ahead in the index - 2009-09-20)
range-diff:
1: 789f7e2872 ! 1: 05eb762d2d unpack-trees.c: add performance tracing
@@ -1,6 +1,6 @@
Author: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
- unpack-trees.c: add performance tracing
+ unpack-trees: add performance tracing
We're going to optimize unpack_trees() a bit in the following
patches. Let's add some tracing to measure how long it takes before
2: 589bed1366 ! 2: 02286ad123 unpack-trees: optimize walking same trees with cache-tree
@@ -32,6 +32,24 @@
0.111793866 0.032933140 s: diff-index
0.587933288 0.398924370 s: git command: /home/pclouds/w/git/git
+ Another measurement from Ben's running "git checkout" with over 500k
+ trees (on the whole series):
+
+ baseline new
+ ----------------------------------------------------------------------
+ 0.535510167 0.556558733 s: read cache .git/index
+ 0.3057373 0.3147105 s: initialize name hash
+ 0.0184082 0.023558433 s: preload index
+ 0.086910967 0.089085967 s: refresh index
+ 7.889590767 2.191554433 s: unpack trees
+ 0.120760833 0.131941267 s: update worktree after a merge
+ 2.2583504 2.572663167 s: repair cache-tree
+ 0.8916137 0.959495233 s: write index, changed mask = 28
+ 3.405199233 0.2710663 s: unpack trees
+ 0.000999667 0.0021554 s: update worktree after a merge
+ 3.4063306 0.273318333 s: diff-index
+ 16.9524923 9.462943133 s: git command: git.exe checkout
+
This command calls unpack_trees() twice, the first time on 2way merge
and the second 1way merge. In both times, "unpack trees" time is
reduced to one third. Overall time reduction is not that impressive of
@@ -39,7 +57,6 @@
repair cache-tree line.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
- Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
diff --git a/unpack-trees.c b/unpack-trees.c
--- a/unpack-trees.c
@@ -170,7 +187,7 @@
}
+/*
-+ * Note that traverse_by_cache_tree() duplicates some logic in this funciton
++ * Note that traverse_by_cache_tree() duplicates some logic in this function
+ * without actually calling it. If you change the logic here you may need to
+ * check and change there as well.
+ */
@@ -189,12 +206,3 @@
static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
{
struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
-@@
- uint64_t start = getnanotime();
-
- if (len > MAX_UNPACK_TREES)
-- die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
-+ die(_("unpack_trees takes at most %d trees"), MAX_UNPACK_TREES);
-
- memset(&el, 0, sizeof(el));
- if (!core_apply_sparse_checkout || !o->update)
3: 7c6f863fc0 = 3: c87b82ffee unpack-trees: reduce malloc in cache-tree walk
4: 6ca17b1138 ! 4: e791cdfc82 unpack-trees: cheaper index update when walking by cache-tree
@@ -40,7 +40,6 @@
attempt should be on that "repair cache-tree" line.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
- Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
diff --git a/cache.h b/cache.h
--- a/cache.h
@@ -119,20 +118,6 @@
free(tree_ce);
if (o->debug_unpack)
printf("Unpacked %d entries from %s to %s using cache-tree\n",
-@@
- if (!ret) {
- if (!o->result.cache_tree)
- o->result.cache_tree = cache_tree();
-+ /*
-+ * TODO: Walk o.src_index->cache_tree, quickly check
-+ * if o->result.cache has the exact same content for
-+ * any valid cache-tree in o.src_index, then we can
-+ * just copy the cache-tree over instead of hashing a
-+ * new tree object.
-+ */
- if (!cache_tree_fully_valid(o->result.cache_tree))
- cache_tree_update(&o->result,
- WRITE_TREE_SILENT |
diff --git a/unpack-trees.h b/unpack-trees.h
--- a/unpack-trees.h
Nguyễn Thái Ngọc Duy (4):
unpack-trees: add performance tracing
unpack-trees: optimize walking same trees with cache-tree
unpack-trees: reduce malloc in cache-tree walk
unpack-trees: cheaper index update when walking by cache-tree
cache-tree.c | 2 +
cache.h | 1 +
read-cache.c | 3 +-
unpack-trees.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++
unpack-trees.h | 1 +
5 files changed, 158 insertions(+), 1 deletion(-)
--
2.18.0.656.gda699b98b3
