fadvise

splice/copy.go

@@ -5,13 +5,28 @@
 package splice
 
 import (
+	"fmt"
 	"io"
 	"os"
 )
 
+// NOTE: DEPRECIATED
+const (
+	FADVISE_NORMAL     = 0x0
+	FADVISE_RANDOM     = 0x1
+	FADVISE_SEQUENTIAL = 0x2
+	FADVISE_WILLNEED   = 0x3
+	FADVISE_DONTNEED   = 0x4
+	FADVISE_NOREUSE    = 0x5
+)
+
 func SpliceCopy(dst *os.File, src *os.File, p *Pair) (int64, error) {
 	total := int64(0)
-
+	st, _ := src.Stat()
+	err := Fadvise64(int(src.Fd()), 0, st.Size(), FADVISE_SEQUENTIAL)
+	if err != nil {
+		fmt.Println("Fadvise64 error:", err)
+	}
 	for {
 		n, err := p.LoadFrom(src.Fd(), p.size)
 		if err != nil {

splice/pair_darwin.go

@@ -32,3 +32,7 @@ func (p *Pair) WriteTo(fd uintptr, n int) (int, error) {
 func (p *Pair) discard() {
 	panic("not implemented")
 }
+
+func Fadvise64(fd int, offset int64, length int64, advice int) error {
+	return nil
+}

splice/pair_linux.go

@@ -58,3 +58,16 @@ func (p *Pair) discard() {
 		log.Panicf("splicing into /dev/null: %v (close R %d '%v', close W %d '%v')", err, p.r, errR, p.w, errW)
 	}
 }
+
+// NOTE: DEPRECIATED
+func Fadvise64(fd int, offset int64, length int64, advice int) error {
+	_, _, errno := syscall.Syscall6(syscall.SYS_FADVISE64,
+		uintptr(fd),
+		uintptr(offset),
+		uintptr(length),
+		uintptr(advice), 0, 0)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}