optimization: substitute time.Now() calls with coarse-grained time in…

… hot paths
satindergrewal · Feb 9, 2017 · 6309f42 · 6309f42
1 parent e113a6d
commit 6309f42
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Showing 5 changed files with 77 additions and 15 deletions.
diff --git a/client.go b/client.go
@@ -1041,7 +1041,7 @@ func (c *HostClient) doNonNilReqResp(req *Request, resp *Response) (bool, error)
 		panic("BUG: resp cannot be nil")
 	}
 
-	atomic.StoreUint32(&c.lastUseTime, uint32(time.Now().Unix()-startTimeUnix))
+	atomic.StoreUint32(&c.lastUseTime, uint32(coarseTimeNow().Unix()-startTimeUnix))
 
 	// Free up resources occupied by response before sending the request,
 	// so the GC may reclaim these resources (e.g. response body).
@@ -1057,7 +1057,7 @@ func (c *HostClient) doNonNilReqResp(req *Request, resp *Response) (bool, error)
 		// Optimization: update write deadline only if more than 25%
 		// of the last write deadline exceeded.
 		// See https://github.com/golang/go/issues/15133 for details.
-		currentTime := time.Now()
+		currentTime := coarseTimeNow()
 		if currentTime.Sub(cc.lastWriteDeadlineTime) > (c.WriteTimeout >> 2) {
 			if err = conn.SetWriteDeadline(currentTime.Add(c.WriteTimeout)); err != nil {
 				c.closeConn(cc)
@@ -1101,7 +1101,7 @@ func (c *HostClient) doNonNilReqResp(req *Request, resp *Response) (bool, error)
 		// Optimization: update read deadline only if more than 25%
 		// of the last read deadline exceeded.
 		// See https://github.com/golang/go/issues/15133 for details.
-		currentTime := time.Now()
+		currentTime := coarseTimeNow()
 		if currentTime.Sub(cc.lastReadDeadlineTime) > (c.ReadTimeout >> 2) {
 			if err = conn.SetReadDeadline(currentTime.Add(c.ReadTimeout)); err != nil {
 				c.closeConn(cc)
@@ -1276,7 +1276,7 @@ func acquireClientConn(conn net.Conn) *clientConn {
 	}
 	cc := v.(*clientConn)
 	cc.c = conn
-	cc.createdTime = time.Now()
+	cc.createdTime = coarseTimeNow()
 	return cc
 }
 
@@ -1288,7 +1288,7 @@ func releaseClientConn(cc *clientConn) {
 var clientConnPool sync.Pool
 
 func (c *HostClient) releaseConn(cc *clientConn) {
-	cc.lastUseTime = time.Now()
+	cc.lastUseTime = coarseTimeNow()
 	c.connsLock.Lock()
 	c.conns = append(c.conns, cc)
 	c.connsLock.Unlock()
@@ -1988,7 +1988,7 @@ func (c *pipelineConnClient) writer(conn net.Conn, stopCh <-chan struct{}) error
 			// Optimization: update write deadline only if more than 25%
 			// of the last write deadline exceeded.
 			// See https://github.com/golang/go/issues/15133 for details.
-			currentTime := time.Now()
+			currentTime := coarseTimeNow()
 			if currentTime.Sub(lastWriteDeadlineTime) > (writeTimeout >> 2) {
 				if err = conn.SetWriteDeadline(currentTime.Add(writeTimeout)); err != nil {
 					w.err = err
@@ -2069,7 +2069,7 @@ func (c *pipelineConnClient) reader(conn net.Conn, stopCh <-chan struct{}) error
 			// Optimization: update read deadline only if more than 25%
 			// of the last read deadline exceeded.
 			// See https://github.com/golang/go/issues/15133 for details.
-			currentTime := time.Now()
+			currentTime := coarseTimeNow()
 			if currentTime.Sub(lastReadDeadlineTime) > (readTimeout >> 2) {
 				if err = conn.SetReadDeadline(currentTime.Add(readTimeout)); err != nil {
 					w.err = err

diff --git a/coarseTime.go b/coarseTime.go
@@ -0,0 +1,25 @@
+package fasthttp
+
+import (
+	"sync/atomic"
+	"time"
+)
+
+func coarseTimeNow() time.Time {
+	tp := coarseTime.Load().(*time.Time)
+	return *tp
+}
+
+func init() {
+	t := time.Now()
+	coarseTime.Store(&t)
+	go func() {
+		for {
+			time.Sleep(time.Second)
+			t := time.Now()
+			coarseTime.Store(&t)
+		}
+	}()
+}
+
+var coarseTime atomic.Value
diff --git a/coarseTime_test.go b/coarseTime_test.go
@@ -0,0 +1,37 @@
+package fasthttp
+
+import (
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func BenchmarkCoarseTimeNow(b *testing.B) {
+	var zeroTimeCount uint64
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			t := coarseTimeNow()
+			if t.IsZero() {
+				atomic.AddUint64(&zeroTimeCount, 1)
+			}
+		}
+	})
+	if zeroTimeCount > 0 {
+		b.Fatalf("zeroTimeCount must be zero")
+	}
+}
+
+func BenchmarkTimeNow(b *testing.B) {
+	var zeroTimeCount uint64
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			t := time.Now()
+			if t.IsZero() {
+				atomic.AddUint64(&zeroTimeCount, 1)
+			}
+		}
+	})
+	if zeroTimeCount > 0 {
+		b.Fatalf("zeroTimeCount must be zero")
+	}
+}
diff --git a/server.go b/server.go
@@ -1280,7 +1280,7 @@ func (s *Server) Serve(ln net.Listener) error {
 			if time.Since(lastOverflowErrorTime) > time.Minute {
 				s.logger().Printf("The incoming connection cannot be served, because %d concurrent connections are served. "+
 					"Try increasing Server.Concurrency", maxWorkersCount)
-				lastOverflowErrorTime = time.Now()
+				lastOverflowErrorTime = coarseTimeNow()
 			}
 
 			// The current server reached concurrency limit,
@@ -1322,7 +1322,7 @@ func acceptConn(s *Server, ln net.Listener, lastPerIPErrorTime *time.Time) (net.
 				if time.Since(*lastPerIPErrorTime) > time.Minute {
 					s.logger().Printf("The number of connections from %s exceeds MaxConnsPerIP=%d",
 						getConnIP4(c), s.MaxConnsPerIP)
-					*lastPerIPErrorTime = time.Now()
+					*lastPerIPErrorTime = coarseTimeNow()
 				}
 				continue
 			}
@@ -1437,7 +1437,7 @@ func (s *Server) serveConn(c net.Conn) error {
 	serverName := s.getServerName()
 	connRequestNum := uint64(0)
 	connID := nextConnID()
-	currentTime := time.Now()
+	currentTime := coarseTimeNow()
 	connTime := currentTime
 	maxRequestBodySize := s.MaxRequestBodySize
 	if maxRequestBodySize <= 0 {
@@ -1494,7 +1494,7 @@ func (s *Server) serveConn(c net.Conn) error {
 			}
 		}
 
-		currentTime = time.Now()
+		currentTime = coarseTimeNow()
 		ctx.lastReadDuration = currentTime.Sub(ctx.time)
 
 		if err != nil {
@@ -1635,7 +1635,7 @@ func (s *Server) serveConn(c net.Conn) error {
 			break
 		}
 
-		currentTime = time.Now()
+		currentTime = coarseTimeNow()
 	}
 
 	if br != nil {
@@ -1691,7 +1691,7 @@ func (s *Server) updateWriteDeadline(c net.Conn, ctx *RequestCtx, lastDeadlineTi
 	// Optimization: update write deadline only if more than 25%
 	// of the last write deadline exceeded.
 	// See https://github.com/golang/go/issues/15133 for details.
-	currentTime := time.Now()
+	currentTime := coarseTimeNow()
 	if currentTime.Sub(lastDeadlineTime) > (writeTimeout >> 2) {
 		if err := c.SetWriteDeadline(currentTime.Add(writeTimeout)); err != nil {
 			panic(fmt.Sprintf("BUG: error in SetWriteDeadline(%s): %s", writeTimeout, err))
@@ -1874,7 +1874,7 @@ func (ctx *RequestCtx) Init2(conn net.Conn, logger Logger, reduceMemoryUsage boo
 	ctx.connID = nextConnID()
 	ctx.s = fakeServer
 	ctx.connRequestNum = 0
-	ctx.connTime = time.Now()
+	ctx.connTime = coarseTimeNow()
 	ctx.time = ctx.connTime
 
 	keepBodyBuffer := !reduceMemoryUsage

diff --git a/workerpool.go b/workerpool.go
@@ -187,7 +187,7 @@ func (wp *workerPool) getCh() *workerChan {
 }
 
 func (wp *workerPool) release(ch *workerChan) bool {
-	ch.lastUseTime = time.Now()
+	ch.lastUseTime = coarseTimeNow()
 	wp.lock.Lock()
 	if wp.mustStop {
 		wp.lock.Unlock()