code review 5236043: gob: avoid one allocation for every message written.

gob: avoid one copy for every message written.
Plus the need for a second in-memory buffer.
Plays a bit fast and loose with the contents of a byte buffer,
but saves a potentially huge allocation. The gotest
run is about 10% faster overall after this change.

[r, 2011-10-07 21:37:37]

Hello golang-dev@googlegroups.com,

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

[r2, 2011-10-07 21:41:16]

hold on

[r, 2011-10-07 21:45:10]

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

Please take another look.

[gri, 2011-10-08 04:05:11]

LGTM

My only question is why it's not possible to reserve the space before (and
together) with the corresponding write as opposed before the next write. It
would see that the former should be easier to understand and perhaps be simpler.

[r, 2011-10-08 05:14:22]

I don't understand. How can you reserve space before the write when that is
after the data has been encoded in the buffer?

[gri, 2011-10-10 18:45:22]

per verbal discussion, LGTM.
- gri

On Fri, Oct 7, 2011 at 10:14 PM,  <r@golang.org> wrote:
> I don't understand. How can you reserve space before the write when that
> is after the data has been encoded in the buffer?
>
> http://codereview.appspot.com/5236043/
>

[r, 2011-10-10 19:38:54]

*** Submitted as http://code.google.com/p/go/source/detail?r=b4311778f494 ***

gob: avoid one copy for every message written.
Plus the need for a second in-memory buffer.
Plays a bit fast and loose with the contents of a byte buffer,
but saves a potentially huge allocation. The gotest
run is about 10% faster overall after this change.

R=golang-dev, r, gri
CC=golang-dev
http://codereview.appspot.com/5236043