=== modified file 'src/client_side.cc'
--- src/client_side.cc	2013-05-08 03:02:01 +0000
+++ src/client_side.cc	2013-05-12 03:49:19 +0000
@@ -2935,14 +2935,22 @@
     }
 }
 
-static int
+static bool
 connOkToAddRequest(ConnStateData * conn)
 {
-    int result = conn->getConcurrentRequestCount() < (Config.onoff.pipeline_prefetch ? 2 : 1);
+    const int maxReq = (Config.onoff.pipeline_prefetch ? SQUID_PIPELINE_MAX : 1);
+    const bool result = (conn->getConcurrentRequestCount() < maxReq);
+
+    /* TODO: make this more dynamic?
+     * ... false / no pipeline for HTTP/1.0 clients?
+     * ... false if NTLM/Negotiate handshake is being done by the last parsed request
+     * ie, pipeline prefetch non-auth requests, halt during connection-auth,
+     *     and resume pipeline prefetching after authed.
+     */
 
     if (!result) {
-        debugs(33, 3, HERE << conn->clientConnection << " max concurrent requests reached");
-        debugs(33, 5, HERE << conn->clientConnection << " defering new request until one is done");
+        debugs(33, 3, conn->clientConnection << " max concurrent requests reached (" << maxReq << ")");
+        debugs(33, 5, conn->clientConnection << " defering new request until one is done");
     }
 
     return result;
@@ -2970,7 +2978,7 @@
         if (in.notYetUsed == 0)
             break;
 
-        /* Limit the number of concurrent requests to 2 */
+        /* Limit the number of concurrent requests to SQUID_PIPELINE_MAX */
         if (!connOkToAddRequest(this)) {
             break;
         }

=== modified file 'src/client_side.h'
--- src/client_side.h	2013-04-04 06:15:00 +0000
+++ src/client_side.h	2013-05-12 03:33:35 +0000
@@ -175,10 +175,30 @@
 class ServerBump;
 }
 #endif
+
+/** Maximum number of pipelined requests to pre-parse.
+ *
+ * Squid can pre-parse requests on a persistent connection and queue them for
+ * service while waiting for a leading transaction to complete. This value
+ * defines how many requests may be pre-parsed when pipeline_prefetch
+ * directive in squid.conf is set to ON and teh client is using a persistent
+ * connection.
+ *
+ * It is generally better to leave most pipelined requests in TCP buffers,
+ * which provides some push-back on the client sending rate.
+ *
+ * NP: currently limited to 2 in case there is any hidden code relying on that
+ *     old hard-coded value still hanging around.
+ *     May be set using -D in CXXFLAGS to test other values.
+ */
+#if !defined(SQUID_PIPELINE_MAX)
+#define SQUID_PIPELINE_MAX      2
+#endif
+
 /**
  * Manages a connection to a client.
  *
- * Multiple requests (up to 2) can be pipelined. This object is responsible for managing
+ * Multiple requests (up to SQUID_PIPELINE_MAX) can be pipelined. This object is responsible for managing
  * which one is currently being fulfilled and what happens to the queue if the current one
  * causes the client connection to be closed early.
  *