From a6720955f19ea10bf9569d04480deed25b1bccf7 Mon Sep 17 00:00:00 2001 From: David Turner Date: Fri, 22 Jan 2016 14:58:43 -0500 Subject: [PATCH] unpack-trees: fix accidentally quadratic behavior While unpacking trees (e.g. during git checkout), when we hit a cache entry that's past and outside our path, we cut off iteration. This provides about a 45% speedup on git checkout between master and master^20000 on Twitter's monorepo. Speedup in general will depend on repostitory structure, number of changes, and packfile packing decisions. Signed-off-by: David Turner Signed-off-by: Junio C Hamano --- unpack-trees.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/unpack-trees.c b/unpack-trees.c index 5f541c28c..9f55cc28b 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -695,8 +695,19 @@ static int find_cache_pos(struct traverse_info *info, ++o->cache_bottom; continue; } - if (!ce_in_traverse_path(ce, info)) + if (!ce_in_traverse_path(ce, info)) { + /* + * Check if we can skip future cache checks + * (because we're already past all possible + * entries in the traverse path). + */ + if (info->traverse_path) { + if (strncmp(ce->name, info->traverse_path, + info->pathlen) > 0) + break; + } continue; + } ce_name = ce->name + pfxlen; ce_slash = strchr(ce_name, '/'); if (ce_slash)