diff --git a/clientconn.go b/clientconn.go
index 3dc42f79..87f302fc 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -42,6 +42,7 @@ import (
 	"time"
 
 	"golang.org/x/net/context"
+	"golang.org/x/net/trace"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/transport"
@@ -148,6 +149,9 @@ func Dial(target string, opts ...DialOption) (*ClientConn, error) {
 		target:       target,
 		shutdownChan: make(chan struct{}),
 	}
+	if EnableTracing {
+		cc.events = trace.NewEventLog("grpc.ClientConn", target)
+	}
 	for _, opt := range opts {
 		opt(&cc.dopts)
 	}
@@ -181,6 +185,9 @@ func Dial(target string, opts ...DialOption) (*ClientConn, error) {
 	cc.stateCV = sync.NewCond(&cc.mu)
 	if cc.dopts.block {
 		if err := cc.resetTransport(false); err != nil {
+			cc.mu.Lock()
+			cc.errorf("dial failed: %v", err)
+			cc.mu.Unlock()
 			cc.Close()
 			return nil, err
 		}
@@ -190,6 +197,9 @@ func Dial(target string, opts ...DialOption) (*ClientConn, error) {
 		// Start a goroutine connecting to the server asynchronously.
 		go func() {
 			if err := cc.resetTransport(false); err != nil {
+				cc.mu.Lock()
+				cc.errorf("dial failed: %v", err)
+				cc.mu.Unlock()
 				grpclog.Printf("Failed to dial %s: %v; please retry.", target, err)
 				cc.Close()
 				return
@@ -200,6 +210,22 @@ func Dial(target string, opts ...DialOption) (*ClientConn, error) {
 	return cc, nil
 }
 
+// printf records an event in cc's event log, unless cc has been closed.
+// REQUIRES cc.mu is held.
+func (cc *ClientConn) printf(format string, a ...interface{}) {
+	if cc.events != nil {
+		cc.events.Printf(format, a...)
+	}
+}
+
+// errorf records an error in cc's event log, unless cc has been closed.
+// REQUIRES cc.mu is held.
+func (cc *ClientConn) errorf(format string, a ...interface{}) {
+	if cc.events != nil {
+		cc.events.Errorf(format, a...)
+	}
+}
+
 // ConnectivityState indicates the state of a client connection.
 type ConnectivityState int
 
@@ -239,14 +265,15 @@ type ClientConn struct {
 	authority    string
 	dopts        dialOptions
 	shutdownChan chan struct{}
+	events       trace.EventLog
 
 	mu      sync.Mutex
 	state   ConnectivityState
 	stateCV *sync.Cond
 	// ready is closed and becomes nil when a new transport is up or failed
 	// due to timeout.
-	ready chan struct{}
-	transport    transport.ClientTransport
+	ready     chan struct{}
+	transport transport.ClientTransport
 }
 
 // State returns the connectivity state of the ClientConn
@@ -295,6 +322,7 @@ func (cc *ClientConn) resetTransport(closeTransport bool) error {
 	start := time.Now()
 	for {
 		cc.mu.Lock()
+		cc.printf("connecting")
 		if cc.state == Shutdown {
 			cc.mu.Unlock()
 			return ErrClientConnClosing
@@ -330,6 +358,7 @@ func (cc *ClientConn) resetTransport(closeTransport bool) error {
 		newTransport, err := transport.NewClientTransport(cc.target, &copts)
 		if err != nil {
 			cc.mu.Lock()
+			cc.errorf("transient failure: %v", err)
 			cc.state = TransientFailure
 			cc.stateCV.Broadcast()
 			cc.mu.Unlock()
@@ -339,6 +368,9 @@ func (cc *ClientConn) resetTransport(closeTransport bool) error {
 			}
 			// Fail early before falling into sleep.
 			if cc.dopts.copts.Timeout > 0 && cc.dopts.copts.Timeout < sleepTime+time.Since(start) {
+				cc.mu.Lock()
+				cc.errorf("connection timeout")
+				cc.mu.Unlock()
 				cc.Close()
 				return ErrClientConnTimeout
 			}
@@ -349,6 +381,7 @@ func (cc *ClientConn) resetTransport(closeTransport bool) error {
 			continue
 		}
 		cc.mu.Lock()
+		cc.printf("ready")
 		if cc.state == Shutdown {
 			// cc.Close() has been invoked.
 			cc.mu.Unlock()
@@ -383,6 +416,9 @@ func (cc *ClientConn) transportMonitor() {
 			cc.mu.Unlock()
 			if err := cc.resetTransport(true); err != nil {
 				// The ClientConn is closing.
+				cc.mu.Lock()
+				cc.printf("transport exiting: %v", err)
+				cc.mu.Unlock()
 				grpclog.Printf("grpc: ClientConn.transportMonitor exits due to: %v", err)
 				return
 			}
@@ -433,6 +469,10 @@ func (cc *ClientConn) Close() error {
 	}
 	cc.state = Shutdown
 	cc.stateCV.Broadcast()
+	if cc.events != nil {
+		cc.events.Finish()
+		cc.events = nil
+	}
 	if cc.ready != nil {
 		close(cc.ready)
 		cc.ready = nil
diff --git a/server.go b/server.go
index feb29887..d0a0e9a8 100644
--- a/server.go
+++ b/server.go
@@ -39,6 +39,7 @@ import (
 	"io"
 	"net"
 	"reflect"
+	"runtime"
 	"strings"
 	"sync"
 
@@ -79,11 +80,12 @@ type service struct {
 
 // Server is a gRPC server to serve RPC requests.
 type Server struct {
-	opts  options
-	mu    sync.Mutex
-	lis   map[net.Listener]bool
-	conns map[transport.ServerTransport]bool
-	m     map[string]*service // service name -> service info
+	opts   options
+	mu     sync.Mutex
+	lis    map[net.Listener]bool
+	conns  map[transport.ServerTransport]bool
+	m      map[string]*service // service name -> service info
+	events trace.EventLog
 }
 
 type options struct {
@@ -128,12 +130,33 @@ func NewServer(opt ...ServerOption) *Server {
 		// Set the default codec.
 		opts.codec = protoCodec{}
 	}
-	return &Server{
+	s := &Server{
 		lis:   make(map[net.Listener]bool),
 		opts:  opts,
 		conns: make(map[transport.ServerTransport]bool),
 		m:     make(map[string]*service),
 	}
+	if EnableTracing {
+		_, file, line, _ := runtime.Caller(1)
+		s.events = trace.NewEventLog("grpc.Server", fmt.Sprintf("%s:%d", file, line))
+	}
+	return s
+}
+
+// printf records an event in s's event log, unless s has been stopped.
+// REQUIRES s.mu is held.
+func (s *Server) printf(format string, a ...interface{}) {
+	if s.events != nil {
+		s.events.Printf(format, a...)
+	}
+}
+
+// errorf records an error in s's event log, unless s has been stopped.
+// REQUIRES s.mu is held.
+func (s *Server) errorf(format string, a ...interface{}) {
+	if s.events != nil {
+		s.events.Errorf(format, a...)
+	}
 }
 
 // RegisterService register a service and its implementation to the gRPC
@@ -151,6 +174,7 @@ func (s *Server) RegisterService(sd *ServiceDesc, ss interface{}) {
 func (s *Server) register(sd *ServiceDesc, ss interface{}) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
+	s.printf("RegisterService(%q)", sd.ServiceName)
 	if _, ok := s.m[sd.ServiceName]; ok {
 		grpclog.Fatalf("grpc: Server.RegisterService found duplicate service registration for %q", sd.ServiceName)
 	}
@@ -182,6 +206,7 @@ var (
 // Service returns when lis.Accept fails.
 func (s *Server) Serve(lis net.Listener) error {
 	s.mu.Lock()
+	s.printf("serving")
 	if s.lis == nil {
 		s.mu.Unlock()
 		return ErrServerStopped
@@ -197,12 +222,18 @@ func (s *Server) Serve(lis net.Listener) error {
 	for {
 		c, err := lis.Accept()
 		if err != nil {
+			s.mu.Lock()
+			s.printf("done serving; Accept = %v", err)
+			s.mu.Unlock()
 			return err
 		}
 		var authInfo credentials.AuthInfo
 		if creds, ok := s.opts.creds.(credentials.TransportAuthenticator); ok {
 			c, authInfo, err = creds.ServerHandshake(c)
 			if err != nil {
+				s.mu.Lock()
+				s.errorf("ServerHandshake(%q) failed: %v", c.RemoteAddr(), err)
+				s.mu.Unlock()
 				grpclog.Println("grpc: Server.Serve failed to complete security handshake.")
 				continue
 			}
@@ -215,6 +246,7 @@ func (s *Server) Serve(lis net.Listener) error {
 		}
 		st, err := transport.NewServerTransport("http2", c, s.opts.maxConcurrentStreams, authInfo)
 		if err != nil {
+			s.errorf("NewServerTransport(%q) failed: %v", c.RemoteAddr(), err)
 			s.mu.Unlock()
 			c.Close()
 			grpclog.Println("grpc: Server.Serve failed to create ServerTransport: ", err)
@@ -418,6 +450,12 @@ func (s *Server) Stop() {
 	for c := range cs {
 		c.Close()
 	}
+	s.mu.Lock()
+	if s.events != nil {
+		s.events.Finish()
+		s.events = nil
+	}
+	s.mu.Unlock()
 }
 
 // TestingCloseConns closes all exiting transports but keeps s.lis accepting new