--- libev/ev.pod	2008/05/06 23:42:16	1.151
+++ libev/ev.pod	2008/05/09 15:52:13	1.153
@@ -2982,8 +2982,9 @@
 =item EV_MINIMAL
 
 If you need to shave off some kilobytes of code at the expense of some
-speed, define this symbol to C<1>. Currently only used for gcc to override
-some inlining decisions, saves roughly 30% codesize of amd64.
+speed, define this symbol to C<1>. Currently this is used to override some
+inlining decisions, saves roughly 30% codesize of amd64. It also selects a
+much smaller 2-heap for timer management over the default 4-heap.
 
 =item EV_PID_HASHSIZE
 
@@ -3000,6 +3001,28 @@
 watchers you might want to increase this value (I<must> be a power of
 two).
 
+=item EV_USE_4HEAP
+
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heap, libev uses a 4-heap when this symbol is defined
+to C<1>. The 4-heap uses more complicated (longer) code but has a
+noticable after performance with many (thousands) of watchers.
+
+The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>
+(disabled).
+
+=item EV_HEAP_CACHE_AT
+
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heap, libev can cache the timestamp (I<at>) within
+the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
+which uses 8-12 bytes more per watcher and a few hundred bytes more code,
+but avoids random read accesses on heap changes. This noticably improves
+performance noticably with with many (hundreds) of watchers.
+
+The default is C<1> unless C<EV_MINIMAL> is set in which case it is C<0>
+(disabled).
+
 =item EV_COMMON
 
 By default, all watchers have a C<void *data> member. By redefining
@@ -3178,8 +3201,8 @@
 
 =item Finding the next timer in each loop iteration: O(1)
 
-By virtue of using a binary heap, the next timer is always found at the
-beginning of the storage array.
+By virtue of using a binary or 4-heap, the next timer is always found at a
+fixed position in the storage array.
 
 =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)