internal/impl: add fast-path marshal implementation
This is a port of the v1 table marshaler, with some substantial
cleanup and refactoring.
Benchstat results from the protobuf reference benchmark data comparing the
v1 package with v2, with AllowPartial:true set for the new package. This
is not an apples-to-apples comparison, since v1 doesn't have a way to
disable required field checks. Required field checks in v2 package
currently go through reflection, which performs terribly; my initial
experimentation indicates that fast-path required field checks will
not add a large amount of cost; these results are incomplete but not
wholly inaccurate.
name old time/op new time/op delta
/dataset.google_message3_1.pb/Marshal-12 219ms ± 1% 232ms ± 1% +5.85% (p=0.004 n=6+5)
/dataset.google_message2.pb/Marshal-12 261µs ± 3% 248µs ± 1% -5.14% (p=0.002 n=6+6)
/dataset.google_message1_proto2.pb/Marshal-12 681ns ± 2% 637ns ± 3% -6.53% (p=0.002 n=6+6)
/dataset.google_message1_proto3.pb/Marshal-12 1.10µs ± 8% 0.99µs ± 3% -9.63% (p=0.002 n=6+6)
/dataset.google_message3_3.pb/Marshal-12 44.2ms ± 3% 35.2ms ± 1% -20.28% (p=0.004 n=6+5)
/dataset.google_message4.pb/Marshal-12 91.4ms ± 2% 94.9ms ± 2% +3.78% (p=0.002 n=6+6)
/dataset.google_message3_2.pb/Marshal-12 78.7ms ± 6% 80.8ms ± 4% ~ (p=0.310 n=6+6)
/dataset.google_message3_4.pb/Marshal-12 10.6ms ± 3% 10.6ms ± 8% ~ (p=0.662 n=5+6)
/dataset.google_message3_5.pb/Marshal-12 675ms ± 4% 510ms ± 2% -24.40% (p=0.002 n=6+6)
/dataset.google_message3_1.pb/Marshal 219ms ± 1% 236ms ± 7% +8.06% (p=0.004 n=5+6)
/dataset.google_message2.pb/Marshal 257µs ± 1% 250µs ± 3% ~ (p=0.052 n=5+6)
/dataset.google_message1_proto2.pb/Marshal 685ns ± 1% 628ns ± 1% -8.41% (p=0.008 n=5+5)
/dataset.google_message1_proto3.pb/Marshal 1.08µs ± 1% 0.98µs ± 2% -9.31% (p=0.004 n=5+6)
/dataset.google_message3_3.pb/Marshal 43.7ms ± 1% 35.1ms ± 1% -19.76% (p=0.002 n=6+6)
/dataset.google_message4.pb/Marshal 93.4ms ± 4% 94.9ms ± 2% ~ (p=0.180 n=6+6)
/dataset.google_message3_2.pb/Marshal 105ms ± 2% 98ms ± 7% -6.81% (p=0.009 n=5+6)
/dataset.google_message3_4.pb/Marshal 16.3ms ± 6% 15.7ms ± 3% -3.44% (p=0.041 n=6+6)
/dataset.google_message3_5.pb/Marshal 676ms ± 4% 504ms ± 2% -25.50% (p=0.004 n=6+5)
Change-Id: I72cc4597117f4cf5d236ef505777d49dd4a5f75d
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/171020
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
diff --git a/internal/impl/codec_extension.go b/internal/impl/codec_extension.go
new file mode 100644
index 0000000..b92932d
--- /dev/null
+++ b/internal/impl/codec_extension.go
@@ -0,0 +1,43 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package impl
+
+import (
+ "google.golang.org/protobuf/internal/encoding/wire"
+ piface "google.golang.org/protobuf/runtime/protoiface"
+)
+
+type extensionFieldInfo struct {
+ wiretag uint64
+ tagsize int
+ funcs ifaceCoderFuncs
+}
+
+func (mi *MessageType) extensionFieldInfo(desc *piface.ExtensionDescV1) *extensionFieldInfo {
+ // As of this time (Go 1.12, linux/amd64), an RWMutex benchmarks as faster
+ // than a sync.Map.
+ mi.extensionFieldInfosMu.RLock()
+ e, ok := mi.extensionFieldInfos[desc]
+ mi.extensionFieldInfosMu.RUnlock()
+ if ok {
+ return e
+ }
+
+ etype := extensionTypeFromDesc(desc)
+ wiretag := wire.EncodeTag(etype.Number(), wireTypes[etype.Kind()])
+ e = &extensionFieldInfo{
+ wiretag: wiretag,
+ tagsize: wire.SizeVarint(wiretag),
+ funcs: encoderFuncsForValue(etype, etype.GoType()),
+ }
+
+ mi.extensionFieldInfosMu.Lock()
+ if mi.extensionFieldInfos == nil {
+ mi.extensionFieldInfos = make(map[*piface.ExtensionDescV1]*extensionFieldInfo)
+ }
+ mi.extensionFieldInfos[desc] = e
+ mi.extensionFieldInfosMu.Unlock()
+ return e
+}