diff -r 18085e46caa9 -r a4b81dbe73c1 mercurial/dirstate.py
--- a/mercurial/dirstate.py	Sun Mar 29 23:28:30 2015 -0700
+++ b/mercurial/dirstate.py	Sun Mar 29 18:28:48 2015 -0700
@@ -634,7 +634,9 @@
 
         alldirs = None
         for ff in files:
-            if normalize:
+            # constructing the foldmap is expensive, so don't do it for the
+            # common case where files is ['.']
+            if normalize and ff != '.':
                 nf = normalize(ff, False, True)
             else:
                 nf = ff