code review 9432046: net/http: fewer allocations in the server path

net/http: fewer allocations in the server path

Don't allocate for the Date or Content-Length headers.
A custom Date header formatter replaces use of time.Format.

benchmark                                   old ns/op    new ns/op    delta
BenchmarkClientServer                           67791        64424   -4.97%
BenchmarkClientServerParallel4                  62956        58533   -7.03%
BenchmarkClientServerParallel64                 62043        54789  -11.69%
BenchmarkServer                                254609       229060  -10.03%
BenchmarkServerFakeConnNoKeepAlive              17038        16316   -4.24%
BenchmarkServerFakeConnWithKeepAlive            14184        13226   -6.75%
BenchmarkServerFakeConnWithKeepAliveLite         8591         7532  -12.33%
BenchmarkServerHandlerTypeLen                   10750         9961   -7.34%
BenchmarkServerHandlerNoLen                      9535         8935   -6.29%
BenchmarkServerHandlerNoType                     9858         9362   -5.03%
BenchmarkServerHandlerNoHeader                   7754         6856  -11.58%

benchmark                                  old allocs   new allocs    delta
BenchmarkClientServer                              68           66   -2.94%
BenchmarkClientServerParallel4                     68           66   -2.94%
BenchmarkClientServerParallel64                    68           66   -2.94%
BenchmarkServer                                    21           19   -9.52%
BenchmarkServerFakeConnNoKeepAlive                 32           30   -6.25%
BenchmarkServerFakeConnWithKeepAlive               27           25   -7.41%
BenchmarkServerFakeConnWithKeepAliveLite           12           10  -16.67%
BenchmarkServerHandlerTypeLen                      19           18   -5.26%
BenchmarkServerHandlerNoLen                        17           15  -11.76%
BenchmarkServerHandlerNoType                       17           16   -5.88%
BenchmarkServerHandlerNoHeader                     12           10  -16.67%

Update Issue 5195

[bradfitz, 2013-05-16 01:40:10]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[bradfitz, 2013-05-18 20:26:05]

Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),

Please take another look.

[bradfitz, 2013-05-18 20:27:30]

Now without time.FormatAppend (or without time.Format).

Also, without the gross workaround for Issue 5492 that was in there
previously.

PTAL

benchmark                                   old ns/op    new ns/op    delta
BenchmarkClientServer                           67791        64424   -4.97%
BenchmarkClientServerParallel4                  62956        58533   -7.03%
BenchmarkClientServerParallel64                 62043        54789  -11.69%
BenchmarkServer                                254609       229060  -10.03%
BenchmarkServerFakeConnNoKeepAlive              17038        16316   -4.24%
BenchmarkServerFakeConnWithKeepAlive            14184        13226   -6.75%
BenchmarkServerFakeConnWithKeepAliveLite         8591         7532  -12.33%
BenchmarkServerHandlerTypeLen                   10750         9961   -7.34%
BenchmarkServerHandlerNoLen                      9535         8935   -6.29%
BenchmarkServerHandlerNoType                     9858         9362   -5.03%
BenchmarkServerHandlerNoHeader                   7754         6856  -11.58%

benchmark                                  old allocs   new allocs    delta
BenchmarkClientServer                              68           66   -2.94%
BenchmarkClientServerParallel4                     68           66   -2.94%
BenchmarkClientServerParallel64                    68           66   -2.94%
BenchmarkServer                                    21           19   -9.52%
BenchmarkServerFakeConnNoKeepAlive                 32           30   -6.25%
BenchmarkServerFakeConnWithKeepAlive               27           25   -7.41%
BenchmarkServerFakeConnWithKeepAliveLite           12           10  -16.67%
BenchmarkServerHandlerTypeLen                      19           18   -5.26%
BenchmarkServerHandlerNoLen                        17           15  -11.76%
BenchmarkServerHandlerNoType                       17           16   -5.88%
BenchmarkServerHandlerNoHeader                     12           10  -16.67%




On Sat, May 18, 2013 at 1:26 PM, <bradfitz@golang.org> wrote:

> Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),
>
> Please take another look.
>
>
>
https://codereview.appspot.**com/9432046/<https://codereview.appspot.com/9432...
>

[nigeltao, 2013-05-20 00:52:13]

LGTM.

https://codereview.appspot.com/9432046/diff/16001/src/pkg/net/http/server.go
File src/pkg/net/http/server.go (right):

https://codereview.appspot.com/9432046/diff/16001/src/pkg/net/http/server.go#...
src/pkg/net/http/server.go:662: headerDate          = []byte("Date: ")
Swap the order so that they're sorted alphabetically? Similarly above and below.

https://codereview.appspot.com/9432046/diff/16001/src/pkg/net/http/server.go#...
src/pkg/net/http/server.go:666: // The value receiver, despite copying 5 strings
to the stack,
This comment could do with some wordsmithing.

[bradfitz, 2013-05-20 03:15:47]

*** Submitted as https://code.google.com/p/go/source/detail?r=647f336edfe8 ***

net/http: fewer allocations in the server path

Don't allocate for the Date or Content-Length headers.
A custom Date header formatter replaces use of time.Format.

benchmark                                   old ns/op    new ns/op    delta
BenchmarkClientServer                           67791        64424   -4.97%
BenchmarkClientServerParallel4                  62956        58533   -7.03%
BenchmarkClientServerParallel64                 62043        54789  -11.69%
BenchmarkServer                                254609       229060  -10.03%
BenchmarkServerFakeConnNoKeepAlive              17038        16316   -4.24%
BenchmarkServerFakeConnWithKeepAlive            14184        13226   -6.75%
BenchmarkServerFakeConnWithKeepAliveLite         8591         7532  -12.33%
BenchmarkServerHandlerTypeLen                   10750         9961   -7.34%
BenchmarkServerHandlerNoLen                      9535         8935   -6.29%
BenchmarkServerHandlerNoType                     9858         9362   -5.03%
BenchmarkServerHandlerNoHeader                   7754         6856  -11.58%

benchmark                                  old allocs   new allocs    delta
BenchmarkClientServer                              68           66   -2.94%
BenchmarkClientServerParallel4                     68           66   -2.94%
BenchmarkClientServerParallel64                    68           66   -2.94%
BenchmarkServer                                    21           19   -9.52%
BenchmarkServerFakeConnNoKeepAlive                 32           30   -6.25%
BenchmarkServerFakeConnWithKeepAlive               27           25   -7.41%
BenchmarkServerFakeConnWithKeepAliveLite           12           10  -16.67%
BenchmarkServerHandlerTypeLen                      19           18   -5.26%
BenchmarkServerHandlerNoLen                        17           15  -11.76%
BenchmarkServerHandlerNoType                       17           16   -5.88%
BenchmarkServerHandlerNoHeader                     12           10  -16.67%

Update Issue 5195

R=nigeltao
CC=golang-dev
https://codereview.appspot.com/9432046

https://codereview.appspot.com/9432046/diff/16001/src/pkg/net/http/server.go
File src/pkg/net/http/server.go (right):

https://codereview.appspot.com/9432046/diff/16001/src/pkg/net/http/server.go#...
src/pkg/net/http/server.go:662: headerDate          = []byte("Date: ")
On 2013/05/20 00:52:13, nigeltao wrote:
> Swap the order so that they're sorted alphabetically? Similarly above and
below.

Done.

https://codereview.appspot.com/9432046/diff/16001/src/pkg/net/http/server.go#...
src/pkg/net/http/server.go:666: // The value receiver, despite copying 5 strings
to the stack,
On 2013/05/20 00:52:13, nigeltao wrote:
> This comment could do with some wordsmithing.

Done.