event.xml doc: update to latest improvements

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1807249 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/docs/manual/mod/event.xml b/docs/manual/mod/event.xml
index c92a394dfd19b91bfd70512478cd2067bf691ae0..f1a4fcf93d1f41e545fdf404e95074fccd58e119 100644 (file)
--- a/docs/manual/mod/event.xml
+++ b/docs/manual/mod/event.xml
@@ -102,6 +102,13 @@ of the <directive>AsyncRequestWorkerFactor</directive>.</p>
 
         <p>These improvements are valid for both HTTP/HTTPS connections.</p>
 
+        <p>The above connection states are managed by the listener thread via dedicated queues, that up to 2.4.27 were checked every 100ms
+        to find which connections hit timeout settings like <directive module="mpm_common">Timeout</directive> and
+        <directive module="core">KeepAliveTimeout</directive>. This was a simple and efficient solution, but it presented a downside: the pollset was
+        forcing a wake-up of the listener thread even if there was no need (for example because completely idle), wasting resources. From 2.4.27
+        these queues are completely managed via an event based logic, not relying anymore on active polling.
+        Resource constrained environments, like embedded servers, may benefit from this improvement.</p>
+
     </section>
 
     <section id="graceful-close"><title>Graceful process termination and Scoreboard usage</title>