code review 72590045: test: speed up chan/select5

test: speed up chan/select5

No functional changes.

Generating shorter functions improves compilation time. On my laptop, this test's running time goes from 5.5s to 1.5s; the wall clock time to run all tests goes down 1s. On Raspberry Pi, this CL cuts 50s off the wall clock time to run all tests.

Fixes issue 7503.

[josharian, 2014-06-17 14:50:43]

Hello golang-codereviews@googlegroups.com,

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

[bradfitz, 2014-06-17 15:42:12]

LGTM if you file a compiler bug about this too



On Tue, Jun 17, 2014 at 7:50 AM, <josharian@gmail.com> wrote:

> Reviewers: golang-codereviews,
>
> Message:
> Hello golang-codereviews@googlegroups.com,
>
> I'd like you to review this change to
> https://code.google.com/p/go
>
>
> Description:
> test: speed up chan/select5
>
> No functional changes.
>
> Generating shorter functions improves compilation time. On my laptop,
> this test's running time goes from 5.5s to 1.5s; the wall clock time to
> run all tests goes down 1s. On Raspberry Pi, this CL cuts 50s off the
> wall clock time to run all tests.
>
> Fixes issue 7503.
>
> Please review this at https://codereview.appspot.com/72590045/
>
> Affected files (+3, -3 lines):
>   M test/chan/select5.go
>
>
> Index: test/chan/select5.go
> ===================================================================
> --- a/test/chan/select5.go
> +++ b/test/chan/select5.go
> @@ -27,16 +27,16 @@
>         fmt.Fprintln(out, header)
>         a := new(arg)
>
> -       // Generate each kind of test as a separate function to avoid
> +       // Generate each test as a separate function to avoid
>         // hitting the 6g optimizer with one enormous function.
>         // If we name all the functions init we don't have to
>         // maintain a list of which ones to run.
>         do := func(t *template.Template) {
> -               fmt.Fprintln(out, `func init() {`)
>                 for ; next(); a.reset() {
> +                       fmt.Fprintln(out, `func init() {`)
>                         run(t, a, out)
> +                       fmt.Fprintln(out, `}`)
>                 }
> -               fmt.Fprintln(out, `}`)
>         }
>
>         do(recv)
>
>
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[josharian, 2014-06-17 16:05:47]

> file a compiler bug about this too

Filed issue 8225, although in CL 74380043, rsc made a comment that makes me
think he didn't consider the time change significant enough to warrant an issue.

[josharian, 2014-06-17 16:07:23]

*** Submitted as https://code.google.com/p/go/source/detail?r=d34804fa2c11 ***

test: speed up chan/select5

No functional changes.

Generating shorter functions improves compilation time. On my laptop, this
test's running time goes from 5.5s to 1.5s; the wall clock time to run all tests
goes down 1s. On Raspberry Pi, this CL cuts 50s off the wall clock time to run
all tests.

Fixes issue 7503.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/72590045

[dave_cheney.net, 2014-06-17 21:54:48]

Wow. Thank you.