perf: 用类型布局缓存 + 指针偏移寻址重写热路径

将实验目录 experiment/fastx 的实现合入主实现,替换原来逐次反射的做法。实现方式: - 类型布局缓存: 首次遇到某类型时把字段偏移量构建成描述符存入全局缓存, 字段查找从按名线性比较变成 O(1) map 查表 (rfx_typedesc.go) - 指针偏移寻址: 取字段时用基址+偏移量直接算地址, 不再构造中间 reflect.Value (unsafeptr.go, 全部 unsafe 代码集中在这一个文件) - 零分配路径解析: 路径按需切片遍历, 不再为每次 Get 分配临时切片 (path.go) - 标量直读: String/Int/Bool/Float64 在类型匹配时直接按机器类型读内存, 绕开 interface 装箱和 cast 转换语义复杂、调用频次低的操作(复合类型赋值、Append、Delete、容器转换)仍走原 reflect 实现, 保留为冷路径 refx (rfx_reflect.go), 避免重写引入行为偏差。新增包级泛型函数 Get[T](r, path...), 按路径直接取出目标类型, 零内存分配。语义与 r.Get(path...).Xxx() 严格等价, 不改动任何现有接口。性能对比(同进程同数据, -benchmem -count=6 中位数): - Get 嵌套 + String 150.6ns/7allocs -> 50.7ns/2allocs 2.97x - Get 4 层深路径 234.1ns/10allocs -> 68.9ns/2allocs 3.40x - Set 单层 65.8ns/2allocs -> 18.1ns/0allocs 3.64x - Set 嵌套 122.1ns/3allocs -> 35.5ns/0allocs 3.44x - Exists 127.4ns/5allocs -> 37.2ns/1alloc 3.42x - 访问器 String 15.0ns/1alloc -> 1.3ns/0allocs 11.8x - Get[string] 泛型直取 -> 29.9ns/0allocs 5.04x 两处不快: map 键访问 1.25x(map 无稳定布局, 仍走 reflect); New 构造 0.67x(多一次描述符缓存查找, 一次性成本)。内存安全: 未导出字段在读和写两处显式拦截 —— reflect.NewAt 构造的 Value 不带只读标记, 语言层面的导出规则保护在 unsafe 路径上失效, 必须自己拦。不变式与评审要点见 unsafeptr.go 顶部注释。测试: 新增 703 个用例全部通过, 含 go test -race。其中接口契约逐方法对拍(含 panic 错误信息逐字比对)、标量转换全矩阵对拍、 []any 内嵌 R、循环引用等边角场景, 均以保留下来的 refx 作为参照实现做差分验证。合并过程中据此发现并修复 11 处行为偏差。
2026-08-28 16:37:04 +08:00
parent 1f48635da3
commit 5c9f8bd6e7
16 changed files with 4360 additions and 851 deletions
@@ -0,0 +1,294 @@
+package reflux
+
+// 新实现(rfx: 类型布局缓存 + unsafe 指针运算)与老实现(refx: 逐次 reflect)的对比。
+//
+// 两者在同一个包、同一次进程里跑, 用完全相同的数据结构和路径, 结果可直接比较。
+// newLegacy 构造的就是合并前的实现, 见 rfx_contract_test.go。
+
+import "testing"
+
+type benchAddress struct {
+	City    string
+	Street  string
+	ZipCode int
+}
+
+type benchPerson struct {
+	Name    string
+	Age     int
+	Email   string
+	Address benchAddress
+	Tags    []string
+	Meta    map[string]string
+}
+
+func newBenchPerson() *benchPerson {
+	return &benchPerson{
+		Name:    "Benchmark",
+		Age:     30,
+		Address: benchAddress{City: "TestCity", ZipCode: 100000},
+		Tags:    []string{"a", "b", "c"},
+		Meta:    map[string]string{"k": "v"},
+	}
+}
+
+type benchDeep4 struct{ B benchDeep3 }
+type benchDeep3 struct{ C benchDeep2 }
+type benchDeep2 struct{ D benchDeep1 }
+type benchDeep1 struct{ Leaf string }
+
+var (
+	benchStr  string
+	benchInt  int
+	benchR    R
+	benchBool bool
+)
+
+// ---------------------------------------------------------------------------
+// 参照基准线: 纯 Go 字段访问
+// ---------------------------------------------------------------------------
+
+func BenchmarkPlainGoGet(b *testing.B) {
+	p := newBenchPerson()
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = p.Address.City
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Get: 嵌套字段
+// ---------------------------------------------------------------------------
+
+func BenchmarkGetLegacy(b *testing.B) {
+	r := newLegacy(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Address", "City").String()
+	}
+}
+
+func BenchmarkGetNew(b *testing.B) {
+	r := New(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Address", "City").String()
+	}
+}
+
+func BenchmarkGetGeneric(b *testing.B) {
+	r := New(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = Get[string](r, "Address", "City")
+	}
+}
+
+// 点号路径
+func BenchmarkGetDottedLegacy(b *testing.B) {
+	r := newLegacy(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Address.City").String()
+	}
+}
+
+func BenchmarkGetDottedNew(b *testing.B) {
+	r := New(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Address.City").String()
+	}
+}
+
+// 4 层深路径
+func BenchmarkGetDeepLegacy(b *testing.B) {
+	r := newLegacy(&benchDeep4{B: benchDeep3{C: benchDeep2{D: benchDeep1{Leaf: "deep"}}}})
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("B", "C", "D", "Leaf").String()
+	}
+}
+
+func BenchmarkGetDeepNew(b *testing.B) {
+	r := New(&benchDeep4{B: benchDeep3{C: benchDeep2{D: benchDeep1{Leaf: "deep"}}}})
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("B", "C", "D", "Leaf").String()
+	}
+}
+
+func BenchmarkGetDeepGeneric(b *testing.B) {
+	r := New(&benchDeep4{B: benchDeep3{C: benchDeep2{D: benchDeep1{Leaf: "deep"}}}})
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = Get[string](r, "B", "C", "D", "Leaf")
+	}
+}
+
+// slice 下标
+func BenchmarkGetSliceIndexLegacy(b *testing.B) {
+	r := newLegacy(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Tags", "1").String()
+	}
+}
+
+func BenchmarkGetSliceIndexNew(b *testing.B) {
+	r := New(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Tags", "1").String()
+	}
+}
+
+// map 键
+func BenchmarkGetMapKeyLegacy(b *testing.B) {
+	r := newLegacy(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Meta", "k").String()
+	}
+}
+
+func BenchmarkGetMapKeyNew(b *testing.B) {
+	r := New(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = r.Get("Meta", "k").String()
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Set
+// ---------------------------------------------------------------------------
+
+func BenchmarkSetLegacy(b *testing.B) {
+	r := newLegacy(&benchPerson{})
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		r.Set("Name", "TestName")
+	}
+}
+
+func BenchmarkSetNew(b *testing.B) {
+	r := New(&benchPerson{})
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		r.Set("Name", "TestName")
+	}
+}
+
+func BenchmarkSetNestedLegacy(b *testing.B) {
+	r := newLegacy(&benchPerson{})
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		r.Set("Address.City", "TestCity")
+	}
+}
+
+func BenchmarkSetNestedNew(b *testing.B) {
+	r := New(&benchPerson{})
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		r.Set("Address.City", "TestCity")
+	}
+}
+
+// ---------------------------------------------------------------------------
+// 访问器: 纯类型转换开销(循环外先取到目标值)
+// ---------------------------------------------------------------------------
+
+func BenchmarkAccessorStringLegacy(b *testing.B) {
+	v := newLegacy(newBenchPerson()).Get("Address.City")
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = v.String()
+	}
+}
+
+func BenchmarkAccessorStringNew(b *testing.B) {
+	v := New(newBenchPerson()).Get("Address.City")
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchStr = v.String()
+	}
+}
+
+func BenchmarkAccessorIntLegacy(b *testing.B) {
+	v := newLegacy(newBenchPerson()).Get("Age")
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchInt = v.Int()
+	}
+}
+
+func BenchmarkAccessorIntNew(b *testing.B) {
+	v := New(newBenchPerson()).Get("Age")
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchInt = v.Int()
+	}
+}
+
+// ---------------------------------------------------------------------------
+// 其它 API
+// ---------------------------------------------------------------------------
+
+func BenchmarkExistsLegacy(b *testing.B) {
+	r := newLegacy(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchBool = r.Exists("Address", "City")
+	}
+}
+
+func BenchmarkExistsNew(b *testing.B) {
+	r := New(newBenchPerson())
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchBool = r.Exists("Address", "City")
+	}
+}
+
+func BenchmarkNewPtrLegacy(b *testing.B) {
+	p := newBenchPerson()
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchR = newLegacy(p)
+	}
+}
+
+func BenchmarkNewPtrNew(b *testing.B) {
+	p := newBenchPerson()
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchR = New(p)
+	}
+}