net/http: optimize some io.Copy calls by reusing buffers
Optimize two calls of io.Copy which cannot make use of neither
io.ReaderFrom nor io.WriterTo optimization tricks by replacing them with
io.CopyBuffer with reusable buffers.
First is fallback call to io.Copy when server misses the optimized case
of using sendfile to copy from a regular file to net.TCPConn; second is
use of io.Copy on piped reader/writer when handler implementation uses
http.CloseNotifier interface. One of the notable users of
http.CloseNotifier is httputil.ReverseProxy.
benchmark old ns/op new ns/op delta
BenchmarkCloseNotifier-4 309591 303388 -2.00%
benchmark old allocs new allocs delta
BenchmarkCloseNotifier-4 50 49 -2.00%
benchmark old bytes new bytes delta
BenchmarkCloseNotifier-4 36168 3140 -91.32%
Fixes #12455
Change-Id: I512e6aa2f1aeed2ed00246afb3350c819b65b87e
Reviewed-on: https://go-review.googlesource.com/14177
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/net/http/serve_test.go b/src/net/http/serve_test.go
index d51417e..7840742 100644
--- a/src/net/http/serve_test.go
+++ b/src/net/http/serve_test.go
@@ -3685,3 +3685,35 @@
<-conn.closec
}
}
+
+func BenchmarkCloseNotifier(b *testing.B) {
+ b.ReportAllocs()
+ b.StopTimer()
+ sawClose := make(chan bool)
+ ts := httptest.NewServer(HandlerFunc(func(rw ResponseWriter, req *Request) {
+ <-rw.(CloseNotifier).CloseNotify()
+ sawClose <- true
+ }))
+ defer ts.Close()
+ tot := time.NewTimer(5 * time.Second)
+ defer tot.Stop()
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ conn, err := net.Dial("tcp", ts.Listener.Addr().String())
+ if err != nil {
+ b.Fatalf("error dialing: %v", err)
+ }
+ _, err = fmt.Fprintf(conn, "GET / HTTP/1.1\r\nConnection: keep-alive\r\nHost: foo\r\n\r\n")
+ if err != nil {
+ b.Fatal(err)
+ }
+ conn.Close()
+ tot.Reset(5 * time.Second)
+ select {
+ case <-sawClose:
+ case <-tot.C:
+ b.Fatal("timeout")
+ }
+ }
+ b.StopTimer()
+}
diff --git a/src/net/http/server.go b/src/net/http/server.go
index 2c01fee..f525815 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -179,7 +179,9 @@
c.sr.r = pr
c.sr.Unlock()
go func() {
- _, err := io.Copy(pw, readSource)
+ bufp := copyBufPool.Get().(*[]byte)
+ defer copyBufPool.Put(bufp)
+ _, err := io.CopyBuffer(pw, readSource, *bufp)
if err == nil {
err = io.EOF
}
@@ -423,7 +425,9 @@
return 0, err
}
if !ok || !regFile {
- return io.Copy(writerOnly{w}, src)
+ bufp := copyBufPool.Get().(*[]byte)
+ defer copyBufPool.Put(bufp)
+ return io.CopyBuffer(writerOnly{w}, src, *bufp)
}
// sendfile path:
@@ -487,6 +491,13 @@
bufioWriter4kPool sync.Pool
)
+var copyBufPool = sync.Pool{
+ New: func() interface{} {
+ b := make([]byte, 32*1024)
+ return &b
+ },
+}
+
func bufioWriterPool(size int) *sync.Pool {
switch size {
case 2 << 10:
