From 5ed72c94fb3ec2ecdc9ba663446c26128bd703cf Mon Sep 17 00:00:00 2001
From: markt <markt@13f79535-47bb-0310-9956-ffa450edef68>
Date: Thu, 5 May 2011 15:01:46 +0000
Subject: [PATCH] Add disableKeepAlivePercentage attribute to the HTTP-BIO
 connector

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1099834 13f79535-47bb-0310-9956-ffa450edef68
---
 java/org/apache/coyote/http11/Http11Processor.java | 20 ++++++++++++++++++--
 java/org/apache/coyote/http11/Http11Protocol.java  | 19 +++++++++++++++++++
 webapps/docs/changelog.xml                         |  5 +++++
 webapps/docs/config/http.xml                       |  8 ++++++++
 4 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/java/org/apache/coyote/http11/Http11Processor.java b/java/org/apache/coyote/http11/Http11Processor.java
index 94dc4c7cb..bff093cc0 100644
--- a/java/org/apache/coyote/http11/Http11Processor.java
+++ b/java/org/apache/coyote/http11/Http11Processor.java
@@ -118,6 +118,12 @@ public class Http11Processor extends AbstractHttp11Processor {
     protected JIoEndpoint endpoint;
 
 
+    /**
+     * The percentage of threads that have to be in use before keep-alive is
+     * disabled to aid scalability.
+     */
+    private int disableKeepAlivePercentage = 75;
+
     // --------------------------------------------------------- Public Methods
 
 
@@ -137,6 +143,16 @@ public class Http11Processor extends AbstractHttp11Processor {
     }
 
 
+    public int getDisableKeepAlivePercentage() {
+        return disableKeepAlivePercentage;
+    }
+
+
+    public void setDisableKeepAlivePercentage(int disableKeepAlivePercentage) {
+        this.disableKeepAlivePercentage = disableKeepAlivePercentage;
+    }
+
+
     /**
      * Process pipelined HTTP requests on the specified socket.
      *
@@ -181,8 +197,8 @@ public class Http11Processor extends AbstractHttp11Processor {
                     / endpoint.getMaxThreads();     
         }   
         // Disable keep-alive if we are running low on threads      
-        if (threadRatio > 75) {     
-            keepAliveLeft = 1;      
+        if (threadRatio > getDisableKeepAlivePercentage()) {     
+            keepAliveLeft = 1;
         }
 
         try {
diff --git a/java/org/apache/coyote/http11/Http11Protocol.java b/java/org/apache/coyote/http11/Http11Protocol.java
index 8c41dc33b..b55efacff 100644
--- a/java/org/apache/coyote/http11/Http11Protocol.java
+++ b/java/org/apache/coyote/http11/Http11Protocol.java
@@ -82,6 +82,23 @@ public class Http11Protocol extends AbstractHttp11JsseProtocol {
     protected Http11ConnectionHandler cHandler;
 
 
+    // ------------------------------------------------ HTTP specific properties
+    // ------------------------------------------ managed in the ProtocolHandler
+
+    private int disableKeepAlivePercentage = 75;
+    public int getDisableKeepAlivePercentage() {
+        return disableKeepAlivePercentage;
+    }
+    public void setDisableKeepAlivePercentage(int disableKeepAlivePercentage) {
+        if (disableKeepAlivePercentage < 0) {
+            this.disableKeepAlivePercentage = 0;
+        } else if (disableKeepAlivePercentage > 100) {
+            this.disableKeepAlivePercentage = 100;
+        } else {
+            this.disableKeepAlivePercentage = disableKeepAlivePercentage;
+        }
+    }
+    
     // ----------------------------------------------------- JMX related methods
 
     @Override
@@ -239,6 +256,8 @@ public class Http11Protocol extends AbstractHttp11JsseProtocol {
             processor.setSocketBuffer(proto.getSocketBuffer());
             processor.setMaxSavePostSize(proto.getMaxSavePostSize());
             processor.setServer(proto.getServer());
+            processor.setDisableKeepAlivePercentage(
+                    proto.getDisableKeepAlivePercentage());
             register(processor);
             return processor;
         }
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 54f3350eb..6a9317237 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -160,6 +160,11 @@
         Improve handling in AJP connectors of the case where too large a AJP
         packet is received. (markt) 
       </fix>
+      <fix>
+        Restore the automatic disabling of HTTP keep-alive with the BIO
+        connector once 75% of the processing threads are in use and make the
+        threshold configurable. (markt)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Jasper">
diff --git a/webapps/docs/config/http.xml b/webapps/docs/config/http.xml
index bf619a958..483f1049e 100644
--- a/webapps/docs/config/http.xml
+++ b/webapps/docs/config/http.xml
@@ -549,6 +549,14 @@
     
     <attributes>
 
+      <attribute name="disableKeepAlivePercentage" required="false">
+        <p>The percentage of processing threads that have to be in use before
+        HTTP keep-alives are disabled to improve scalability. Values less than
+        <code>0</code> will be changed to <code>0</code> and values greater than
+        <code>100</code> will be changed to <code>100</code>. If not specified,
+        the default value is <code>75</code>.</p>
+      </attribute>
+
       <attribute name="maxConnections" required="false">
         <p>The maximum number of connections that the server will accept and
         process at any given time. When this number has been reached, the server
-- 
2.11.0