Revert "Remove CoarseTime"

This reverts commit f2ddaffc31.

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()
@@ -1991,7 +1991,7 @@ 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
@@ -2072,7 +2072,7 @@ 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

coarseTime.go

@@ -0,0 +1,28 @@
+package fasthttp
+
+import (
+	"sync/atomic"
+	"time"
+)
+
+// CoarseTimeNow returns the current time truncated to the nearest second.
+//
+// This is a faster alternative to time.Now().
+func CoarseTimeNow() time.Time {
+	tp := coarseTime.Load().(*time.Time)
+	return *tp
+}
+
+func init() {
+	t := time.Now().Truncate(time.Second)
+	coarseTime.Store(&t)
+	go func() {
+		for {
+			time.Sleep(time.Second)
+			t := time.Now().Truncate(time.Second)
+			coarseTime.Store(&t)
+		}
+	}()
+}
+
+var coarseTime atomic.Value

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")
+	}
+}

server.go

@@ -598,13 +598,18 @@ func (ctx *RequestCtx) ConnID() uint64 {
 	return ctx.connID
 }
 
-// Time returns RequestHandler call time.
+// Time returns RequestHandler call time truncated to the nearest second.
+//
+// Call time.Now() at the beginning of RequestHandler in order to obtain
+// precise RequestHandler call time.
 func (ctx *RequestCtx) Time() time.Time {
 	return ctx.time
 }
 
 // ConnTime returns the time server starts serving the connection
 // the current request came from.
+//
+// The returned time is truncated to the nearest second.
 func (ctx *RequestCtx) ConnTime() time.Time {
 	return ctx.connTime
 }
@@ -1314,7 +1319,7 @@ 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,
@@ -1356,7 +1361,7 @@ 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
 			}
@@ -1471,7 +1476,7 @@ 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 {
@@ -1528,7 +1533,7 @@ func (s *Server) serveConn(c net.Conn) error {
 			}
 		}
 
-		currentTime = time.Now()
+		currentTime = CoarseTimeNow()
 		ctx.lastReadDuration = currentTime.Sub(ctx.time)
 
 		if err != nil {
@@ -1669,7 +1674,7 @@ func (s *Server) serveConn(c net.Conn) error {
 			break
 		}
 
-		currentTime = time.Now()
+		currentTime = CoarseTimeNow()
 	}
 
 	if br != nil {
@@ -1725,7 +1730,7 @@ 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))
@@ -1908,7 +1913,7 @@ 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

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()