Asynchronously retry update on congestion
We now get notifications when the output buffer empties, and we
already caught incoming RTT pongs, meaning we can now react at the
proper time to retry a congested update rather than use a timer.
diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index 0f4ca94..3a072ef 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -75,8 +75,7 @@
pingCounter(0), congestionTimer(this),
server(server_), updates(false),
updateRenderedCursor(false), removeRenderedCursor(false),
- continuousUpdates(false), encodeManager(this),
- updateTimer(this), pointerEventTime(0),
+ continuousUpdates(false), encodeManager(this), pointerEventTime(0),
accessRights(AccessDefault), startTime(time(0))
{
setStreams(&sock->inStream(), &sock->outStream());
@@ -196,6 +195,10 @@
try {
setSocketTimeouts();
sock->outStream().flush();
+ // Flushing the socket might release an update that was previously
+ // delayed because of congestion.
+ if (sock->outStream().bufferUsage() == 0)
+ writeFramebufferUpdate();
} catch (rdr::Exception &e) {
close(e.str());
}
@@ -741,9 +744,7 @@
bool VNCSConnectionST::handleTimeout(Timer* t)
{
try {
- if (t == &updateTimer)
- writeFramebufferUpdate();
- else if (t == &congestionTimer)
+ if (t == &congestionTimer)
updateCongestion();
else if (t == &queryConnectTimer) {
if (state() == RFBSTATE_QUERYING)
@@ -939,8 +940,6 @@
bool needNewUpdateInfo;
bool drawRenderedCursor;
- updateTimer.stop();
-
// We're in the middle of processing a command that's supposed to be
// synchronised. Allowing an update to slip out right now might violate
// that synchronisation.
@@ -960,10 +959,8 @@
// Check that we actually have some space on the link and retry in a
// bit if things are congested.
- if (isCongested()) {
- updateTimer.start(50);
+ if (isCongested())
return;
- }
// In continuous mode, we will be outputting at least three distinct
// messages. We need to aggregate these in order to not clog up TCP's