--- a/mercurial/help/config.txt Tue Jan 12 23:56:48 2016 +0900
+++ b/mercurial/help/config.txt Thu Jan 14 13:34:59 2016 -0800
@@ -2037,3 +2037,27 @@
Number of CPUs to use for parallel operations. A zero or
negative value is treated as ``use the default``.
(default: 4 or the number of CPUs on the system, whichever is larger)
+
+``backgroundclose``
+ Whether to enable closing file handles on background threads during certain
+ operations. Some platforms aren't very efficient at closing file
+ handles that have been written or appened to. By performing file closing
+ on background threads, file write rate can increase substantially.
+ (default: true on Windows, false elsewhere)
+
+``backgroundcloseminfilecount``
+ Minimum number of files required to trigger background file closing.
+ Operations not writing this many files won't start background close
+ threads.
+ (default: 2048)
+
+``backgroundclosemaxqueue``
+ The maximum number of opened file handles waiting to be closed in the
+ background. This option only has an effect if ``backgroundclose`` is
+ enabled.
+ (default: 384)
+
+``backgroundclosethreadcount``
+ Number of threads to process background file closes. Only relevant if
+ ``backgroundclose`` is enabled.
+ (default: 4)