From eb9688ff65a3f7fb28ee6488be728fc72e42d5d6 Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nico@cam.org>
Date: Mon, 10 Dec 2007 14:19:32 -0500
Subject: pack-objects: more threaded load balancing fix with often changed
 paths

The code that splits the object list amongst work threads tries to do so
on "path" boundaries not to prevent good delta matches.  However, in
some cases, a few paths may largely dominate the hash distribution and
it is not possible to have good load balancing without ignoring those
boundaries.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index 250dc56..7dd0d7f 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -1709,6 +1709,16 @@ static void ll_find_deltas(struct object_entry **list, unsigned list_size,
 				list++;
 				sub_size--;
 			}
+			if (!sub_size) {
+				/*
+				 * It is possible for some "paths" to have
+				 * so many objects that no hash boundary
+				 * might be found.  Let's just steal the
+				 * exact half in that case.
+				 */
+				sub_size = victim->remaining / 2;
+				list -= sub_size;
+			}
 			target->list = list;
 			victim->list_size -= sub_size;
 			victim->remaining -= sub_size;
-- 
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