code review 147720043: encoding/gob: speedup encoding

encoding/gob: speedup encoding

Replace typeLock with copy-on-write map using atomic.Value.

benchmark                               old ns/op     new ns/op     delta
BenchmarkEndToEndPipe                   7722          7709          -0.17%
BenchmarkEndToEndPipe-2                 5114          4344          -15.06%
BenchmarkEndToEndPipe-4                 3192          2429          -23.90%
BenchmarkEndToEndPipe-8                 1833          1438          -21.55%
BenchmarkEndToEndPipe-16                1332          983           -26.20%
BenchmarkEndToEndPipe-32                1444          675           -53.25%
BenchmarkEndToEndByteBuffer             6474          6019          -7.03%
BenchmarkEndToEndByteBuffer-2           4280          2810          -34.35%
BenchmarkEndToEndByteBuffer-4           2264          1774          -21.64%
BenchmarkEndToEndByteBuffer-8           1275          979           -23.22%
BenchmarkEndToEndByteBuffer-16          1257          753           -40.10%
BenchmarkEndToEndByteBuffer-32          1342          644           -52.01%
BenchmarkEndToEndArrayByteBuffer        727725        671349        -7.75%
BenchmarkEndToEndArrayByteBuffer-2      394079        320473        -18.68%
BenchmarkEndToEndArrayByteBuffer-4      211785        178175        -15.87%
BenchmarkEndToEndArrayByteBuffer-8      141003        118857        -15.71%
BenchmarkEndToEndArrayByteBuffer-16     139249        86367         -37.98%
BenchmarkEndToEndArrayByteBuffer-32     144128        73454         -49.04%

[dvyukov, 2014-09-17 03:00:58]

Hello golang-codereviews@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go/

[r, 2014-09-17 23:23:31]

https://codereview.appspot.com/147720043/diff/40001/src/encoding/gob/type.go
File src/encoding/gob/type.go (right):

https://codereview.appspot.com/147720043/diff/40001/src/encoding/gob/type.go#...
src/encoding/gob/type.go:691: // It's updated using copy-on-write technique.
Readers just do an atomic load
It's updated copy-on-write.

https://codereview.appspot.com/147720043/diff/40001/src/encoding/gob/type.go#...
src/encoding/gob/type.go:715: func getTypeInfoSlow(ut *userTypeInfo, rt
reflect.Type) (*typeInfo, error) {
never was a fan of names like Slow and Fast in function names.
how about

// buildTypeInfo constructs the type information for the type and stores it in
the type info map.
func buileTypeInfo

[dvyukov, 2014-09-18 03:40:59]

PTAL

https://codereview.appspot.com/147720043/diff/40001/src/encoding/gob/type.go
File src/encoding/gob/type.go (right):

https://codereview.appspot.com/147720043/diff/40001/src/encoding/gob/type.go#...
src/encoding/gob/type.go:691: // It's updated using copy-on-write technique.
Readers just do an atomic load
On 2014/09/17 23:23:30, r wrote:
> It's updated copy-on-write.

Done.

https://codereview.appspot.com/147720043/diff/40001/src/encoding/gob/type.go#...
src/encoding/gob/type.go:715: func getTypeInfoSlow(ut *userTypeInfo, rt
reflect.Type) (*typeInfo, error) {
On 2014/09/17 23:23:30, r wrote:
> never was a fan of names like Slow and Fast in function names.
> how about
> 
> // buildTypeInfo constructs the type information for the type and stores it in
> the type info map.
> func buileTypeInfo
> 

Done.

[r, 2014-09-18 06:07:35]

LGTM

[dvyukov, 2014-09-18 17:12:32]

*** Submitted as https://code.google.com/p/go/source/detail?r=41418a795cb0 ***

encoding/gob: speedup encoding

Replace typeLock with copy-on-write map using atomic.Value.

benchmark                               old ns/op     new ns/op     delta
BenchmarkEndToEndPipe                   7722          7709          -0.17%
BenchmarkEndToEndPipe-2                 5114          4344          -15.06%
BenchmarkEndToEndPipe-4                 3192          2429          -23.90%
BenchmarkEndToEndPipe-8                 1833          1438          -21.55%
BenchmarkEndToEndPipe-16                1332          983           -26.20%
BenchmarkEndToEndPipe-32                1444          675           -53.25%
BenchmarkEndToEndByteBuffer             6474          6019          -7.03%
BenchmarkEndToEndByteBuffer-2           4280          2810          -34.35%
BenchmarkEndToEndByteBuffer-4           2264          1774          -21.64%
BenchmarkEndToEndByteBuffer-8           1275          979           -23.22%
BenchmarkEndToEndByteBuffer-16          1257          753           -40.10%
BenchmarkEndToEndByteBuffer-32          1342          644           -52.01%
BenchmarkEndToEndArrayByteBuffer        727725        671349        -7.75%
BenchmarkEndToEndArrayByteBuffer-2      394079        320473        -18.68%
BenchmarkEndToEndArrayByteBuffer-4      211785        178175        -15.87%
BenchmarkEndToEndArrayByteBuffer-8      141003        118857        -15.71%
BenchmarkEndToEndArrayByteBuffer-16     139249        86367         -37.98%
BenchmarkEndToEndArrayByteBuffer-32     144128        73454         -49.04%

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://codereview.appspot.com/147720043