From 8af1a7086c3aabcd490711a5609d019afa3606ec Mon Sep 17 00:00:00 2001
From: Arceliar <Arceliar@users.noreply.github.com>
Date: Sun, 18 Aug 2019 12:29:07 -0500
Subject: [PATCH] when a link becomes idle and packet are buffered that the
 link could send, send at least 65535 bytes worth instead of 1 packet, this
 reduces syscall overhead when small packets are sent through the network

---
 src/yggdrasil/debug.go  |  6 ++--
 src/yggdrasil/switch.go | 64 ++++++++++++++++++++++++-----------------
 2 files changed, 41 insertions(+), 29 deletions(-)

diff --git a/src/yggdrasil/debug.go b/src/yggdrasil/debug.go
index ff3bbe7..9f7707e 100644
--- a/src/yggdrasil/debug.go
+++ b/src/yggdrasil/debug.go
@@ -556,8 +556,10 @@ func DEBUG_simLinkPeers(p, q *peer) {
 	goWorkers := func(source, dest *peer) {
 		source.linkOut = make(chan []byte, 1)
 		send := make(chan []byte, 1)
-		source.out = func(bs []byte) {
-			send <- bs
+		source.out = func(bss [][]byte) {
+			for _, bs := range bss {
+				send <- bs
+			}
 		}
 		go source.linkLoop()
 		go func() {
diff --git a/src/yggdrasil/switch.go b/src/yggdrasil/switch.go
index 9be8554..cc316d1 100644
--- a/src/yggdrasil/switch.go
+++ b/src/yggdrasil/switch.go
@@ -784,39 +784,49 @@ func (t *switchTable) handleIdle(port switchPort) bool {
 	if to == nil {
 		return true
 	}
-	var best string
-	var bestPriority float64
+	var packets [][]byte
+	var psize int
 	t.queues.cleanup(t)
 	now := time.Now()
-	for streamID, buf := range t.queues.bufs {
-		// Filter over the streams that this node is closer to
-		// Keep the one with the smallest queue
-		packet := buf.packets[0]
-		coords := switch_getPacketCoords(packet.bytes)
-		priority := float64(now.Sub(packet.time)) / float64(buf.size)
-		if priority > bestPriority && t.portIsCloser(coords, port) {
-			best = streamID
-			bestPriority = priority
+	for psize < 65535 {
+		var best string
+		var bestPriority float64
+		for streamID, buf := range t.queues.bufs {
+			// Filter over the streams that this node is closer to
+			// Keep the one with the smallest queue
+			packet := buf.packets[0]
+			coords := switch_getPacketCoords(packet.bytes)
+			priority := float64(now.Sub(packet.time)) / float64(buf.size)
+			if priority > bestPriority && t.portIsCloser(coords, port) {
+				best = streamID
+				bestPriority = priority
+			}
 		}
-	}
-	if bestPriority != 0 {
-		buf := t.queues.bufs[best]
-		var packet switch_packetInfo
-		// TODO decide if this should be LIFO or FIFO
-		packet, buf.packets = buf.packets[0], buf.packets[1:]
-		buf.size -= uint64(len(packet.bytes))
-		t.queues.size -= uint64(len(packet.bytes))
-		if len(buf.packets) == 0 {
-			delete(t.queues.bufs, best)
+		if bestPriority != 0 {
+			buf := t.queues.bufs[best]
+			var packet switch_packetInfo
+			// TODO decide if this should be LIFO or FIFO
+			packet, buf.packets = buf.packets[0], buf.packets[1:]
+			buf.size -= uint64(len(packet.bytes))
+			t.queues.size -= uint64(len(packet.bytes))
+			if len(buf.packets) == 0 {
+				delete(t.queues.bufs, best)
+			} else {
+				// Need to update the map, since buf was retrieved by value
+				t.queues.bufs[best] = buf
+			}
+			packets = append(packets, packet.bytes)
+			psize += len(packet.bytes)
 		} else {
-			// Need to update the map, since buf was retrieved by value
-			t.queues.bufs[best] = buf
+			// Finished finding packets
+			break
 		}
-		to.sendPackets([][]byte{packet.bytes})
-		return true
-	} else {
-		return false
 	}
+	if len(packets) > 0 {
+		to.sendPackets(packets)
+		return true
+	}
+	return false
 }
 
 // The switch worker does routing lookups and sends packets to where they need to be