Index: java/org/apache/coyote/Response.java
===================================================================
--- java/org/apache/coyote/Response.java	(revision 1493385)
+++ java/org/apache/coyote/Response.java	(working copy)
@@ -107,6 +107,7 @@
 
     // General informations
     private long contentWritten = 0;
+    private long commitTime = -1;
 
     /**
      * Holds request error exception.
@@ -219,9 +220,20 @@
 
 
     public void setCommitted(boolean v) {
+        if (v && !this.commited) {
+            this.commitTime = System.currentTimeMillis();
+        }
         this.commited = v;
     }
 
+    /**
+     * Return the time the response was committed (based on System.currentTimeMillis).
+     *
+     * @return the time the response was committed
+     */
+    public long getCommitTime() {
+        return commitTime;
+    }
 
     // -----------------Error State --------------------
 
@@ -354,7 +366,7 @@
      */
     public void sendHeaders() {
         action(ActionCode.COMMIT, this);
-        commited = true;
+        setCommitted(true);
     }
 
 
@@ -522,6 +534,7 @@
         status = 200;
         message = null;
         commited = false;
+        commitTime = -1;
         errorException = null;
         headers.clear();
         listener = null;
Index: java/org/apache/catalina/valves/AccessLogValve.java
===================================================================
--- java/org/apache/catalina/valves/AccessLogValve.java	(revision 1493385)
+++ java/org/apache/catalina/valves/AccessLogValve.java	(working copy)
@@ -1754,6 +1754,22 @@
     }
 
     /**
+     * write time until first byte is written (commit time) in millis - %F
+     */
+    protected static class FirstByteTimeElement implements AccessLogElement {
+        @Override
+        public void addElement(CharArrayWriter buf, Date date, Request request, Response response, long time) {
+            long commitTime = response.getCoyoteResponse().getCommitTime();
+            if (commitTime == -1) {
+                buf.append('-');
+            } else {
+                long delta = commitTime - request.getCoyoteRequest().getStartTime();
+                buf.append(Long.toString(delta));
+            }
+        }
+    }
+
+    /**
      * write Query string (prepended with a '?' if it exists) - %q
      */
     protected static class QueryElement implements AccessLogElement {
@@ -2065,6 +2081,8 @@
             return new ByteSentElement(false);
         case 'D':
             return new ElapsedTimeElement(true);
+        case 'F':
+            return new FirstByteTimeElement();
         case 'h':
             return new HostElement();
         case 'H':