diff --git a/rlp/decode.go b/rlp/decode.go index 976780971..e4262b64d 100644 --- a/rlp/decode.go +++ b/rlp/decode.go @@ -245,7 +245,7 @@ func makeListDecoder(typ reflect.Type, tag tags) (decoder, error) { } return decodeByteSlice, nil } - etypeinfo := cachedTypeInfo1(etype, tags{}) + etypeinfo := theTC.infoWhileGenerating(etype, tags{}) if etypeinfo.decoderErr != nil { return nil, etypeinfo.decoderErr } @@ -424,7 +424,7 @@ func zeroFields(structval reflect.Value, fields []field) { // makePtrDecoder creates a decoder that decodes into the pointer's element type. func makePtrDecoder(typ reflect.Type, tag tags) (decoder, error) { etype := typ.Elem() - etypeinfo := cachedTypeInfo1(etype, tags{}) + etypeinfo := theTC.infoWhileGenerating(etype, tags{}) switch { case etypeinfo.decoderErr != nil: return nil, etypeinfo.decoderErr diff --git a/rlp/encode.go b/rlp/encode.go index b7e74a133..2e1b0102c 100644 --- a/rlp/encode.go +++ b/rlp/encode.go @@ -517,7 +517,7 @@ func writeInterface(val reflect.Value, w *encbuf) error { } func makeSliceWriter(typ reflect.Type, ts tags) (writer, error) { - etypeinfo := cachedTypeInfo1(typ.Elem(), tags{}) + etypeinfo := theTC.infoWhileGenerating(typ.Elem(), tags{}) if etypeinfo.writerErr != nil { return nil, etypeinfo.writerErr } @@ -585,7 +585,7 @@ func makeStructWriter(typ reflect.Type) (writer, error) { } func makePtrWriter(typ reflect.Type, ts tags) (writer, error) { - etypeinfo := cachedTypeInfo1(typ.Elem(), tags{}) + etypeinfo := theTC.infoWhileGenerating(typ.Elem(), tags{}) if etypeinfo.writerErr != nil { return nil, etypeinfo.writerErr } diff --git a/rlp/encode_test.go b/rlp/encode_test.go index 74e8ededc..0177bb035 100644 --- a/rlp/encode_test.go +++ b/rlp/encode_test.go @@ -23,6 +23,7 @@ import ( "io" "io/ioutil" "math/big" + "runtime" "sync" "testing" @@ -480,3 +481,35 @@ func BenchmarkEncodeBigInts(b *testing.B) { } } } + +func BenchmarkEncodeConcurrentInterface(b *testing.B) { + type struct1 struct { + A string + B *big.Int + C [20]byte + } + value := []interface{}{ + uint(999), + &struct1{A: "hello", B: big.NewInt(0xFFFFFFFF)}, + [10]byte{1, 2, 3, 4, 5, 6}, + []string{"yeah", "yeah", "yeah"}, + } + + var wg sync.WaitGroup + for cpu := 0; cpu < runtime.NumCPU(); cpu++ { + wg.Add(1) + go func() { + defer wg.Done() + + var buffer bytes.Buffer + for i := 0; i < b.N; i++ { + buffer.Reset() + err := Encode(&buffer, value) + if err != nil { + panic(err) + } + } + }() + } + wg.Wait() +} diff --git a/rlp/typecache.go b/rlp/typecache.go index 3910dcf08..62553d3b5 100644 --- a/rlp/typecache.go +++ b/rlp/typecache.go @@ -21,13 +21,10 @@ import ( "reflect" "strings" "sync" + "sync/atomic" ) -var ( - typeCacheMutex sync.RWMutex - typeCache = make(map[typekey]*typeinfo) -) - +// typeinfo is an entry in the type cache. type typeinfo struct { decoder decoder decoderErr error // error from makeDecoder @@ -65,41 +62,76 @@ type decoder func(*Stream, reflect.Value) error type writer func(reflect.Value, *encbuf) error +var theTC = newTypeCache() + +type typeCache struct { + cur atomic.Value + + // This lock synchronizes writers. + mu sync.Mutex + next map[typekey]*typeinfo +} + +func newTypeCache() *typeCache { + c := new(typeCache) + c.cur.Store(make(map[typekey]*typeinfo)) + return c +} + func cachedDecoder(typ reflect.Type) (decoder, error) { - info := cachedTypeInfo(typ, tags{}) + info := theTC.info(typ) return info.decoder, info.decoderErr } func cachedWriter(typ reflect.Type) (writer, error) { - info := cachedTypeInfo(typ, tags{}) + info := theTC.info(typ) return info.writer, info.writerErr } -func cachedTypeInfo(typ reflect.Type, tags tags) *typeinfo { - typeCacheMutex.RLock() - info := typeCache[typekey{typ, tags}] - typeCacheMutex.RUnlock() - if info != nil { +func (c *typeCache) info(typ reflect.Type) *typeinfo { + key := typekey{Type: typ} + if info := c.cur.Load().(map[typekey]*typeinfo)[key]; info != nil { return info } - // not in the cache, need to generate info for this type. - typeCacheMutex.Lock() - defer typeCacheMutex.Unlock() - return cachedTypeInfo1(typ, tags) + + // Not in the cache, need to generate info for this type. + return c.generate(typ, tags{}) +} + +func (c *typeCache) generate(typ reflect.Type, tags tags) *typeinfo { + c.mu.Lock() + defer c.mu.Unlock() + + cur := c.cur.Load().(map[typekey]*typeinfo) + if info := cur[typekey{typ, tags}]; info != nil { + return info + } + + // Copy cur to next. + c.next = make(map[typekey]*typeinfo, len(cur)+1) + for k, v := range cur { + c.next[k] = v + } + + // Generate. + info := c.infoWhileGenerating(typ, tags) + + // next -> cur + c.cur.Store(c.next) + c.next = nil + return info } -func cachedTypeInfo1(typ reflect.Type, tags tags) *typeinfo { +func (c *typeCache) infoWhileGenerating(typ reflect.Type, tags tags) *typeinfo { key := typekey{typ, tags} - info := typeCache[key] - if info != nil { - // another goroutine got the write lock first + if info := c.next[key]; info != nil { return info } - // put a dummy value into the cache before generating. - // if the generator tries to lookup itself, it will get + // Put a dummy value into the cache before generating. + // If the generator tries to lookup itself, it will get // the dummy value and won't call itself recursively. - info = new(typeinfo) - typeCache[key] = info + info := new(typeinfo) + c.next[key] = info info.generate(typ, tags) return info } @@ -133,7 +165,7 @@ func structFields(typ reflect.Type) (fields []field, err error) { } else if anyOptional { return nil, fmt.Errorf(`rlp: struct field %v.%s needs "optional" tag`, typ, f.Name) } - info := cachedTypeInfo1(f.Type, tags) + info := theTC.infoWhileGenerating(f.Type, tags) fields = append(fields, field{i, info, tags.optional}) } }