From c742414ab8861b60d009eb739427c6d8bdebc88a Mon Sep 17 00:00:00 2001
From: Patrick McManus <mcmanus@ducksong.com>
Date: Fri, 8 Apr 2011 14:36:47 -0400
Subject: [PATCH] 624739 - sort idle persistent http connections by pereceived
 server cwnd

--HG--
extra : rebase_source : 29c50d0c0e99220bb87b5f584188fad49cc33439
---
 netwerk/protocol/http/nsHttpConnection.cpp    | 25 +++++++++++++------
 netwerk/protocol/http/nsHttpConnection.h      |  3 +++
 netwerk/protocol/http/nsHttpConnectionMgr.cpp | 20 ++++++++++++---
 3 files changed, 37 insertions(+), 11 deletions(-)

diff --git a/netwerk/protocol/http/nsHttpConnection.cpp b/netwerk/protocol/http/nsHttpConnection.cpp
index a3e713e6c74f..47e1a07c4918 100644
--- a/netwerk/protocol/http/nsHttpConnection.cpp
+++ b/netwerk/protocol/http/nsHttpConnection.cpp
@@ -70,6 +70,8 @@ nsHttpConnection::nsHttpConnection()
     , mIdleTimeout(0)
     , mConsiderReusedAfterInterval(0)
     , mConsiderReusedAfterEpoch(0)
+    , mCurrentBytesRead(0)
+    , mMaxBytesRead(0)
     , mKeepAlive(PR_TRUE) // assume to keep-alive by default
     , mKeepAliveMask(PR_TRUE)
     , mSupportsPipelining(PR_FALSE) // assume low-grade server
@@ -161,6 +163,9 @@ nsHttpConnection::Activate(nsAHttpTransaction *trans, PRUint8 caps)
             goto failed_activation;
     }
 
+    // Clear the per activation counter
+    mCurrentBytesRead = 0;
+
     rv = OnOutputStreamReady(mSocketOut);
     
 failed_activation:
@@ -502,6 +507,9 @@ nsHttpConnection::CloseTransaction(nsAHttpTransaction *trans, nsresult reason)
     NS_ASSERTION(trans == mTransaction, "wrong transaction");
     NS_ASSERTION(PR_GetCurrentThread() == gSocketThread, "wrong thread");
 
+    if (mCurrentBytesRead > mMaxBytesRead)
+        mMaxBytesRead = mCurrentBytesRead;
+
     // mask this error code because its not a real error.
     if (reason == NS_BASE_STREAM_CLOSED)
         reason = NS_OK;
@@ -677,13 +685,16 @@ nsHttpConnection::OnSocketReadable()
                 rv = NS_OK;
             again = PR_FALSE;
         }
-        else if (NS_FAILED(mSocketInCondition)) {
-            // continue waiting for the socket if necessary...
-            if (mSocketInCondition == NS_BASE_STREAM_WOULD_BLOCK)
-                rv = mSocketIn->AsyncWait(this, 0, 0, nsnull);
-            else
-                rv = mSocketInCondition;
-            again = PR_FALSE;
+        else {
+            mCurrentBytesRead += n;
+            if (NS_FAILED(mSocketInCondition)) {
+                // continue waiting for the socket if necessary...
+                if (mSocketInCondition == NS_BASE_STREAM_WOULD_BLOCK)
+                    rv = mSocketIn->AsyncWait(this, 0, 0, nsnull);
+                else
+                    rv = mSocketInCondition;
+                again = PR_FALSE;
+            }
         }
         // read more from the socket until error...
     } while (again);
diff --git a/netwerk/protocol/http/nsHttpConnection.h b/netwerk/protocol/http/nsHttpConnection.h
index 1a18033284a1..261c05ce28f2 100644
--- a/netwerk/protocol/http/nsHttpConnection.h
+++ b/netwerk/protocol/http/nsHttpConnection.h
@@ -138,6 +138,7 @@ public:
     nsresult PushBack(const char *data, PRUint32 length) { NS_NOTREACHED("PushBack"); return NS_ERROR_UNEXPECTED; }
     nsresult ResumeSend();
     nsresult ResumeRecv();
+    PRInt64  MaxBytesRead() {return mMaxBytesRead;}
 
     static NS_METHOD ReadFromStream(nsIInputStream *, void *, const char *,
                                     PRUint32, PRUint32, PRUint32 *);
@@ -180,6 +181,8 @@ private:
     PRUint16                        mIdleTimeout;    // value of keep-alive: timeout=
     PRIntervalTime                  mConsiderReusedAfterInterval;
     PRIntervalTime                  mConsiderReusedAfterEpoch;
+    PRInt64                         mCurrentBytesRead;   // data read per activation
+    PRInt64                         mMaxBytesRead;       // max read in 1 activation
 
     PRPackedBool                    mKeepAlive;
     PRPackedBool                    mKeepAliveMask;
diff --git a/netwerk/protocol/http/nsHttpConnectionMgr.cpp b/netwerk/protocol/http/nsHttpConnectionMgr.cpp
index 1b351726b0e2..d233907596c3 100644
--- a/netwerk/protocol/http/nsHttpConnectionMgr.cpp
+++ b/netwerk/protocol/http/nsHttpConnectionMgr.cpp
@@ -1057,12 +1057,24 @@ nsHttpConnectionMgr::OnMsgReclaimConnection(PRInt32, void *param)
 
         if (conn->CanReuse()) {
             LOG(("  adding connection to idle list\n"));
-            // hold onto this connection in the idle list.  we push it to
-            // the end of the list so as to ensure that we'll visit older
-            // connections first before getting to this one.
+            // Keep The idle connection list sorted with the connections that
+            // have moved the largest data pipelines at the front because these
+            // connections have the largest cwnds on the server.
+
+            // The linear search is ok here because the number of idleconns
+            // in a single entry is generally limited to a small number (i.e. 6)
+
+            PRInt32 idx;
+            for (idx = 0; idx < ent->mIdleConns.Length(); idx++) {
+                nsHttpConnection *idleConn = ent->mIdleConns[idx];
+                if (idleConn->MaxBytesRead() < conn->MaxBytesRead())
+                    break;
+            }
+
             NS_ADDREF(conn);
-            ent->mIdleConns.AppendElement(conn);
+            ent->mIdleConns.InsertElementAt(idx, conn);
             mNumIdleConns++;
+
             // If the added connection was first idle connection or has shortest
             // time to live among the idle connections, pruning dead
             // connections needs to be done when it can't be reused anymore.