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/sendfile_windows.go b/src/pkg/net/sendfile_windows.go
index 5012583..e9b9f91 100644
--- a/src/pkg/net/sendfile_windows.go
+++ b/src/pkg/net/sendfile_windows.go
@@ -10,20 +10,6 @@
"syscall"
)
-type sendfileOp struct {
- anOp
- src syscall.Handle // source
- n uint32
-}
-
-func (o *sendfileOp) Submit() (err error) {
- return syscall.TransmitFile(o.fd.sysfd, o.src, o.n, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
-}
-
-func (o *sendfileOp) Name() string {
- return "TransmitFile"
-}
-
// sendFile copies the contents of r to c using the TransmitFile
// system call to minimize copies.
//
@@ -33,7 +19,7 @@
// if handled == false, sendFile performed no work.
//
// Note that sendfile for windows does not suppport >2GB file.
-func sendFile(c *netFD, r io.Reader) (written int64, err error, handled bool) {
+func sendFile(fd *netFD, r io.Reader) (written int64, err error, handled bool) {
var n int64 = 0 // by default, copy until EOF
lr, ok := r.(*io.LimitedReader)
@@ -48,18 +34,18 @@
return 0, nil, false
}
- if err := c.incref(false); err != nil {
+ if err := fd.incref(false); err != nil {
return 0, err, true
}
- defer c.decref()
- c.wio.Lock()
- defer c.wio.Unlock()
-
- var o sendfileOp
- o.Init(c, 'w')
- o.n = uint32(n)
- o.src = syscall.Handle(f.Fd())
- done, err := iosrv.ExecIO(&o)
+ defer fd.decref()
+ o := &fd.wop
+ o.mu.Lock()
+ defer o.mu.Unlock()
+ o.qty = uint32(n)
+ o.handle = syscall.Handle(f.Fd())
+ done, err := iosrv.ExecIO(o, "TransmitFile", func(o *operation) error {
+ return syscall.TransmitFile(o.fd.sysfd, o.handle, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
+ })
if err != nil {
return 0, err, false
}
