global.go   | 7 ++++++-
 peerconn.go | 2 +-

diff --git a/global.go b/global.go
index 6542ac393daaf324d9b2427db851b559d707aea1..ff237c8ee1edda4f9d464d08d9db1bb49c7fa670 100644
--- a/global.go
+++ b/global.go
@@ -24,10 +24,15 @@ func defaultPeerExtensionBytes() PeerExtensionBits {
 	return pp.NewPeerExtensionBytes(pp.ExtensionBitDHT, pp.ExtensionBitExtended, pp.ExtensionBitFast)
 }
 
+func init() {
+	torrent.Set("peers supporting extension", &peersSupportingExtension)
+}
+
 // I could move a lot of these counters to their own file, but I suspect they
 // may be attached to a Client someday.
 var (
-	torrent = expvar.NewMap("torrent")
+	torrent                  = expvar.NewMap("torrent")
+	peersSupportingExtension expvar.Map
 
 	pieceHashedCorrect    = expvar.NewInt("pieceHashedCorrect")
 	pieceHashedNotCorrect = expvar.NewInt("pieceHashedNotCorrect")
diff --git a/peerconn.go b/peerconn.go
index 535ba737fca0765413868c03bed9d03b5b8cbff0..41e8662d295f31dcd93e81720ccbf5cbb31b157b 100644
--- a/peerconn.go
+++ b/peerconn.go
@@ -1308,7 +1308,7 @@ 		c.PeerListenPort = d.Port
 		c.PeerPrefersEncryption = d.Encryption
 		for name, id := range d.M {
 			if _, ok := c.PeerExtensionIDs[name]; !ok {
-				torrent.Add(fmt.Sprintf("peers supporting extension %q", name), 1)
+				peersSupportingExtension.Add(string(name), 1)
 			}
 			c.PeerExtensionIDs[name] = id
 		}