code review 140510043: runtime: add timing test for iterate/delete map idiom.

runtime: add timing test for iterate/delete map idiom.

[khr, 2014-09-11 04:07:22]

Hello iant@golang.org (cc: golang-codereviews@googlegroups.com),

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

[bradfitz, 2014-09-11 04:13:52]

LGTM


On Wed, Sep 10, 2014 at 9:07 PM, <khr@golang.org> wrote:

> Reviewers: iant,
>
> Message:
> Hello iant@golang.org (cc: golang-codereviews@googlegroups.com),
>
> I'd like you to review this change to
> https://code.google.com/p/go/
>
>
> Description:
> runtime: add timing test for iterate/delete map idiom.
>
> Please review this at https://codereview.appspot.com/140510043/
>
> Affected files (+18, -0 lines):
>   M test/maplinear.go
>
>
> Index: test/maplinear.go
> ===================================================================
> --- a/test/maplinear.go
> +++ b/test/maplinear.go
> @@ -140,4 +140,22 @@
>                         m[complex(float64(i), float64(i))] = 1
>                 }
>         })
> +
> +       // ~70ms on a 1.6GHz Zeon.
> +       // The iterate/delete idiom currently takes expected
> +       // O(n lg n) time.  Fortunately, the checkLinear test
> +       // leaves enough wiggle room to include n lg n time
> +       // (it actually tests for O(n^log_2(3)).
> +       checkLinear("iterdelete", 10000, func(n int) {
> +               m := map[int]int{}
> +               for i := 0; i < n; i++ {
> +                       m[i] = i
> +               }
> +               for i := 0; i < n; i++ {
> +                       for k := range m {
> +                               delete(m, k)
> +                               break
> +                       }
> +               }
> +       })
>  }
>
>
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[iant, 2014-09-11 04:15:25]

LGTM

[khr, 2014-09-11 05:54:09]

*** Submitted as https://code.google.com/p/go/source/detail?r=4057ec7e5d74 ***

runtime: add timing test for iterate/delete map idiom.

LGTM=bradfitz, iant
R=iant, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/140510043

[josharian, 2014-09-12 01:24:38]

This test just failed on the linux-amd64 builder:
http://build.golang.org/log/a072ace9911212c913e018a36fd28e0bbdd17200.
Maybe there wasn't enough wiggle room after all.

[bradfitz, 2014-09-12 14:39:55]

Could somebody adjust or disable the test then?


On Thu, Sep 11, 2014 at 9:23 PM, Josh Bleecher Snyder <josharian@gmail.com>
wrote:

> This test just failed on the linux-amd64 builder:
> http://build.golang.org/log/a072ace9911212c913e018a36fd28e0bbdd17200.
> Maybe there wasn't enough wiggle room after all.
>

[josharian, 2014-09-12 18:56:10]

> Could somebody adjust or disable the test then?

I'm fixing the test. I'll send a CL in a bit.