pack-objects: update size heuristucs.

We used to omit delta base candidates that is much bigger than
the target, but delta size does not grow when we delete more, so
that was not a very good heuristics.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/pack-objects.c b/pack-objects.c
index c0acc460bb9df0313e314eb2cf48363b2458082c..66043381317b118dd525d547479d81b75d6b89f8 100644 (file)
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -1032,12 +1032,6 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
                max_depth -= cur_entry->delta_limit;
        }
 
                max_depth -= cur_entry->delta_limit;
        }
 

-       size = cur_entry->size;
-       oldsize = old_entry->size;
-       sizediff = oldsize > size ? oldsize - size : size - oldsize;
-
-       if (size < 50)
-               return -1;

        if (old_entry->depth >= max_depth)
                return 0;
 
        if (old_entry->depth >= max_depth)
                return 0;
 


@@ -1048,9 +1042,12 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
         * more space-efficient (deletes don't have to say _what_ they
         * delete).
         */
         * more space-efficient (deletes don't have to say _what_ they
         * delete).
         */

+       size = cur_entry->size;

        max_size = size / 2 - 20;
        if (cur_entry->delta)
                max_size = cur_entry->delta_size-1;
        max_size = size / 2 - 20;
        if (cur_entry->delta)
                max_size = cur_entry->delta_size-1;

+       oldsize = old_entry->size;
+       sizediff = oldsize < size ? size - oldsize : 0;

        if (sizediff >= max_size)
                return 0;
        delta_buf = diff_delta(old->data, oldsize,
        if (sizediff >= max_size)
                return 0;
        delta_buf = diff_delta(old->data, oldsize,


@@ -1109,6 +1106,9 @@ static void find_deltas(struct object_entry **list, int window, int depth)
                         */
                        continue;
 
                         */
                        continue;
 

+               if (entry->size < 50)
+                       continue;
+

                free(n->data);
                n->entry = entry;
                n->data = read_sha1_file(entry->sha1, type, &size);
                free(n->data);
                n->entry = entry;
                n->data = read_sha1_file(entry->sha1, type, &size);