net: reduce number of memory allocations during IO operations
Embed all data necessary for read/write operations directly into netFD.
benchmark old ns/op new ns/op delta
BenchmarkTCP4Persistent 27669 23341 -15.64%
BenchmarkTCP4Persistent-2 18173 12558 -30.90%
BenchmarkTCP4Persistent-4 10390 7319 -29.56%
This change will intentionally break all builders to see
how many allocations they do per read/write.
This will be fixed soon afterwards.
R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/12413043
diff --git a/src/pkg/net/tcp_test.go b/src/pkg/net/tcp_test.go
index f356f92..dedd41d 100644
--- a/src/pkg/net/tcp_test.go
+++ b/src/pkg/net/tcp_test.go
@@ -6,6 +6,7 @@
import (
"fmt"
+ "io"
"reflect"
"runtime"
"sync"
@@ -327,3 +328,46 @@
ln.Close()
wg.Wait()
}
+
+func TestTCPReadWriteMallocs(t *testing.T) {
+ maxMallocs := 0
+ switch runtime.GOOS {
+ // Add other OSes if you know how many mallocs they do.
+ case "windows":
+ maxMallocs = 0
+ }
+ ln, err := Listen("tcp", "127.0.0.1:0")
+ if err != nil {
+ t.Fatalf("Listen failed: %v", err)
+ }
+ defer ln.Close()
+ var server Conn
+ errc := make(chan error)
+ go func() {
+ var err error
+ server, err = ln.Accept()
+ errc <- err
+ }()
+ client, err := Dial("tcp", ln.Addr().String())
+ if err != nil {
+ t.Fatalf("Dial failed: %v", err)
+ }
+ if err := <-errc; err != nil {
+ t.Fatalf("Accept failed: %v", err)
+ }
+ defer server.Close()
+ var buf [128]byte
+ mallocs := testing.AllocsPerRun(1000, func() {
+ _, err := server.Write(buf[:])
+ if err != nil {
+ t.Fatalf("Write failed: %v", err)
+ }
+ _, err = io.ReadFull(client, buf[:])
+ if err != nil {
+ t.Fatalf("Read failed: %v", err)
+ }
+ })
+ if int(mallocs) > maxMallocs {
+ t.Fatalf("Got %v allocs, want %v", mallocs, maxMallocs)
+ }
+}
