perf: improve pool performance for pointer types (#147)

Author: abemedia

nilcheck.go

@@ -1,9 +1,6 @@
 package don
 
-import (
-	"reflect"
-	"unsafe"
-)
+import "reflect"
 
 func newNilCheck(zero any) func(v any) bool {
 	typ := reflect.TypeOf(zero)
@@ -19,22 +16,12 @@ func newNilCheck(zero any) func(v any) bool {
 		return func(v any) bool { return v == zero }
 	case reflect.Map:
 		// Return true for and nil map.
-		return func(v any) bool {
-			return (*emptyInterface)(unsafe.Pointer(&v)).ptr == nil
-		}
+		return func(v any) bool { return dataOf(v) == nil }
 	case reflect.Slice:
 		// Return true for nil slice.
-		return func(v any) bool {
-			return (*reflect.SliceHeader)((*emptyInterface)(unsafe.Pointer(&v)).ptr).Data == 0
-		}
+		return func(v any) bool { return (*reflect.SliceHeader)(dataOf(v)).Data == 0 }
 	default:
 		// Return false for all others.
 		return func(v any) bool { return false }
 	}
 }
-
-// emptyInterface is the header for an interface{} value.
-type emptyInterface struct {
-	typ unsafe.Pointer
-	ptr unsafe.Pointer
-}

pool.go

@@ -10,12 +10,6 @@ type pool[T any] interface {
 	Put(*T)
 }
 
-type resetter interface {
-	Reset()
-}
-
-var resetterType = reflect.TypeOf((*resetter)(nil)).Elem()
-
 type requestPool[T any] struct {
 	pool  sync.Pool
 	reset func(*T)
@@ -37,21 +31,17 @@ func newRequestPool[T any](zero T) pool[T] {
 			*v = zero
 		}
 	} else {
+		rtype := dataOf(typ)
 		elem := typ.Elem()
+		elemrtype := dataOf(elem)
+		zero := dataOf(reflect.New(elem).Elem().Interface())
+
 		p.pool.New = func() any {
-			v := reflect.New(elem).Interface().(T) //nolint:forcetypeassert
+			v := packEface(rtype, unsafe_New(elemrtype)).(T) //nolint:forcetypeassert
 			return &v
 		}
-
-		if typ.Implements(resetterType) {
-			p.reset = func(v *T) {
-				any(*v).(resetter).Reset() //nolint:forcetypeassert
-			}
-		} else {
-			zeroValue := reflect.New(elem).Elem()
-			p.reset = func(v *T) {
-				reflect.ValueOf(v).Elem().Elem().Set(zeroValue)
-			}
+		p.reset = func(v *T) {
+			typedmemmove(elemrtype, dataOf(*v), zero)
 		}
 	}
 

pool_test.go

@@ -60,32 +60,4 @@ func TestRequestPool(t *testing.T) {
 			}
 		}
 	})
-
-	t.Run("Resetter", func(t *testing.T) {
-		zero := &itemResetter{}
-		pool := don.NewRequestPool(zero)
-
-		for i := 0; i < 100; i++ {
-			p := pool.Get()
-			v := *p
-			v.String = "test"
-			v.Pointer = &v.String
-			pool.Put(p)
-		}
-
-		for i := 0; i < 100; i++ {
-			if !reflect.DeepEqual(&zero, pool.Get()) {
-				t.Fatal("should be zero value")
-			}
-		}
-	})
-}
-
-type itemResetter struct {
-	String  string
-	Pointer *string
-}
-
-func (ir *itemResetter) Reset() {
-	*ir = itemResetter{}
 }

unsafe.go

@@ -0,0 +1,27 @@
+package don
+
+import "unsafe"
+
+//go:linkname unsafe_New reflect.unsafe_New
+func unsafe_New(unsafe.Pointer) unsafe.Pointer //nolint:revive
+
+//go:linkname typedmemmove reflect.typedmemmove
+func typedmemmove(t, dst, src unsafe.Pointer)
+
+// emptyInterface is the header for an interface{} value.
+type emptyInterface struct {
+	typ unsafe.Pointer
+	ptr unsafe.Pointer
+}
+
+func dataOf(v any) unsafe.Pointer {
+	return (*emptyInterface)(unsafe.Pointer(&v)).ptr
+}
+
+func packEface(typ, ptr unsafe.Pointer) any {
+	var i any
+	e := (*emptyInterface)(unsafe.Pointer(&i))
+	e.typ = typ
+	e.ptr = ptr
+	return i
+}