perf(cloudflared): reuse memory from buffer pool to get better throughput (#161)

* perf(cloudflared): reuse memory from buffer pool to get better throughput

https://github.com/cloudflare/cloudflared/issues/160

buffer/pool.go

@@ -0,0 +1,29 @@
+package buffer
+
+import (
+	"sync"
+)
+
+type Pool struct {
+	// A Pool must not be copied after first use.
+	// https://golang.org/pkg/sync/#Pool
+	buffers sync.Pool
+}
+
+func NewPool(bufferSize int) *Pool {
+	return &Pool{
+		buffers: sync.Pool{
+			New: func() interface{} {
+				return make([]byte, bufferSize)
+			},
+		},
+	}
+}
+
+func (p *Pool) Get() []byte {
+	return p.buffers.Get().([]byte)
+}
+
+func (p *Pool) Put(buf []byte) {
+	p.buffers.Put(buf)
+}

origin/supervisor.go

@@ -11,6 +11,7 @@ import (
 	"github.com/google/uuid"
 	"github.com/sirupsen/logrus"
 
+	"github.com/cloudflare/cloudflared/buffer"
 	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/edgediscovery"
 	"github.com/cloudflare/cloudflared/h2mux"
@@ -62,6 +63,8 @@ type Supervisor struct {
 
 	eventDigestLock *sync.RWMutex
 	eventDigest     []byte
+
+	bufferPool *buffer.Pool
 }
 
 type resolveResult struct {
@@ -96,6 +99,7 @@ func NewSupervisor(config *TunnelConfig, u uuid.UUID) (*Supervisor, error) {
 		logger:            config.Logger.WithField("subsystem", "supervisor"),
 		jwtLock:           &sync.RWMutex{},
 		eventDigestLock:   &sync.RWMutex{},
+		bufferPool:        buffer.NewPool(512 * 1024),
 	}, nil
 }
 
@@ -230,7 +234,7 @@ func (s *Supervisor) startFirstTunnel(ctx context.Context, connectedSignal *sign
 		return
 	}
 
-	err = ServeTunnelLoop(ctx, s, s.config, addr, thisConnID, connectedSignal, s.cloudflaredUUID)
+	err = ServeTunnelLoop(ctx, s, s.config, addr, thisConnID, connectedSignal, s.cloudflaredUUID, s.bufferPool)
 	// If the first tunnel disconnects, keep restarting it.
 	edgeErrors := 0
 	for s.unusedIPs() {
@@ -253,7 +257,7 @@ func (s *Supervisor) startFirstTunnel(ctx context.Context, connectedSignal *sign
 				return
 			}
 		}
-		err = ServeTunnelLoop(ctx, s, s.config, addr, thisConnID, connectedSignal, s.cloudflaredUUID)
+		err = ServeTunnelLoop(ctx, s, s.config, addr, thisConnID, connectedSignal, s.cloudflaredUUID, s.bufferPool)
 	}
 }
 
@@ -272,7 +276,7 @@ func (s *Supervisor) startTunnel(ctx context.Context, index int, connectedSignal
 	if err != nil {
 		return
 	}
-	err = ServeTunnelLoop(ctx, s, s.config, addr, uint8(index), connectedSignal, s.cloudflaredUUID)
+	err = ServeTunnelLoop(ctx, s, s.config, addr, uint8(index), connectedSignal, s.cloudflaredUUID, s.bufferPool)
 }
 
 func (s *Supervisor) newConnectedTunnelSignal(index int) *signal.Signal {

origin/tunnel.go

@@ -20,6 +20,7 @@ import (
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sync/errgroup"
 
+	"github.com/cloudflare/cloudflared/buffer"
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/buildinfo"
 	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/h2mux"
@@ -178,6 +179,7 @@ func ServeTunnelLoop(ctx context.Context,
 	connectionID uint8,
 	connectedSignal *signal.Signal,
 	u uuid.UUID,
+	bufferPool *buffer.Pool,
 ) error {
 	connectionLogger := config.Logger.WithField("connectionID", connectionID)
 	config.Metrics.incrementHaConnections()
@@ -201,6 +203,7 @@ func ServeTunnelLoop(ctx context.Context,
 			connectedFuse,
 			&backoff,
 			u,
+			bufferPool,
 		)
 		if recoverable {
 			if duration, ok := backoff.GetBackoffDuration(ctx); ok {
@@ -223,6 +226,7 @@ func ServeTunnel(
 	connectedFuse *h2mux.BooleanFuse,
 	backoff *BackoffHandler,
 	u uuid.UUID,
+	bufferPool *buffer.Pool,
 ) (err error, recoverable bool) {
 	// Treat panics as recoverable errors
 	defer func() {
@@ -243,7 +247,7 @@ func ServeTunnel(
 	tags["ha"] = connectionTag
 
 	// Returns error from parsing the origin URL or handshake errors
-	handler, originLocalIP, err := NewTunnelHandler(ctx, config, addr, connectionID)
+	handler, originLocalIP, err := NewTunnelHandler(ctx, config, addr, connectionID, bufferPool)
 	if err != nil {
 		errLog := logger.WithError(err)
 		switch err.(type) {
@@ -500,6 +504,8 @@ type TunnelHandler struct {
 	connectionID      string
 	logger            *log.Logger
 	noChunkedEncoding bool
+
+	bufferPool *buffer.Pool
 }
 
 // NewTunnelHandler returns a TunnelHandler, origin LAN IP and error
@@ -507,6 +513,7 @@ func NewTunnelHandler(ctx context.Context,
 	config *TunnelConfig,
 	addr *net.TCPAddr,
 	connectionID uint8,
+	bufferPool *buffer.Pool,
 ) (*TunnelHandler, string, error) {
 	originURL, err := validation.ValidateUrl(config.OriginUrl)
 	if err != nil {
@@ -522,6 +529,7 @@ func NewTunnelHandler(ctx context.Context,
 		connectionID:      uint8ToString(connectionID),
 		logger:            config.Logger,
 		noChunkedEncoding: config.NoChunkedEncoding,
+		bufferPool:        bufferPool,
 	}
 	if h.httpClient == nil {
 		h.httpClient = http.DefaultTransport
@@ -642,7 +650,9 @@ func (h *TunnelHandler) serveHTTP(stream *h2mux.MuxedStream, req *http.Request)
 	} else {
 		// Use CopyBuffer, because Copy only allocates a 32KiB buffer, and cross-stream
 		// compression generates dictionary on first write
-		io.CopyBuffer(stream, response.Body, make([]byte, 512*1024))
+		buf := h.bufferPool.Get()
+		defer h.bufferPool.Put(buf)
+		io.CopyBuffer(stream, response.Body, buf)
 	}
 	return response, nil
 }

originservice/originservice.go

@@ -12,6 +12,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/cloudflare/cloudflared/buffer"
 	"github.com/cloudflare/cloudflared/h2mux"
 	"github.com/cloudflare/cloudflared/hello"
 	"github.com/cloudflare/cloudflared/log"
@@ -33,6 +34,7 @@ type HTTPService struct {
 	client          http.RoundTripper
 	originURL       *url.URL
 	chunkedEncoding bool
+	bufferPool      *buffer.Pool
 }
 
 func NewHTTPService(transport http.RoundTripper, url *url.URL, chunkedEncoding bool) OriginService {
@@ -40,6 +42,7 @@ func NewHTTPService(transport http.RoundTripper, url *url.URL, chunkedEncoding b
 		client:          transport,
 		originURL:       url,
 		chunkedEncoding: chunkedEncoding,
+		bufferPool:      buffer.NewPool(512 * 1024),
 	}
 }
 
@@ -71,7 +74,9 @@ func (hc *HTTPService) Proxy(stream *h2mux.MuxedStream, req *http.Request) (*htt
 	} else {
 		// Use CopyBuffer, because Copy only allocates a 32KiB buffer, and cross-stream
 		// compression generates dictionary on first write
-		io.CopyBuffer(stream, resp.Body, make([]byte, 512*1024))
+		buf := hc.bufferPool.Get()
+		defer hc.bufferPool.Put(buf)
+		io.CopyBuffer(stream, resp.Body, buf)
 	}
 	return resp, nil
 }
@@ -146,6 +151,7 @@ type HelloWorldService struct {
 	listener   net.Listener
 	originURL  *url.URL
 	shutdownC  chan struct{}
+	bufferPool *buffer.Pool
 }
 
 func NewHelloWorldService(transport http.RoundTripper) (OriginService, error) {
@@ -165,6 +171,7 @@ func NewHelloWorldService(transport http.RoundTripper) (OriginService, error) {
 			Host:   listener.Addr().String(),
 		},
 		shutdownC:  shutdownC,
+		bufferPool: buffer.NewPool(512 * 1024),
 	}, nil
 }
 
@@ -184,7 +191,9 @@ func (hwc *HelloWorldService) Proxy(stream *h2mux.MuxedStream, req *http.Request
 
 	// Use CopyBuffer, because Copy only allocates a 32KiB buffer, and cross-stream
 	// compression generates dictionary on first write
-	io.CopyBuffer(stream, resp.Body, make([]byte, 512*1024))
+	buf := hwc.bufferPool.Get()
+	defer hwc.bufferPool.Put(buf)
+	io.CopyBuffer(stream, resp.Body, buf)
 
 	return resp, nil
 }