code review 125720044: runtime: use better hash for non-empty interface

runtime: use better hash for non-empty interface

The implementation 'return 0' results in too many collisions.

[rsc, 2014-08-06 18:15:23]

Hello golang-codereviews@googlegroups.com (cc: adonovan, iant, khr, r),

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

[adonovan, 2014-08-06 18:46:01]

On 2014/08/06 18:15:23, rsc wrote:
> Hello mailto:golang-codereviews@googlegroups.com (cc: adonovan, iant, khr, r),
> 
> I'd like you to review this change to
> https://code.google.com/p/go/

Thanks Russ.  

Do we have any benchmarks that exercise hash table performance and that might
have caught this, or could be easily extended to do so?

[rsc, 2014-08-06 18:49:21]

On Wed, Aug 6, 2014 at 2:46 PM, <adonovan@google.com> wrote:

> On 2014/08/06 18:15:23, rsc wrote:
>
>> Hello mailto:golang-codereviews@googlegroups.com (cc: adonovan, iant,
>>
> khr, r),
>
>  I'd like you to review this change to
>> https://code.google.com/p/go/
>>
>
> Thanks Russ.
>
> Do we have any benchmarks that exercise hash table performance and that
> might have caught this, or could be easily extended to do so?


test/mapnan.go might be a start.

[khr1, 2014-08-06 20:16:12]

LGTM.

I have some tests in CL 121030043 that I'll be sure to check in.



On Wed, Aug 6, 2014 at 11:49 AM, Russ Cox <rsc@golang.org> wrote:

> On Wed, Aug 6, 2014 at 2:46 PM, <adonovan@google.com> wrote:
>
>> On 2014/08/06 18:15:23, rsc wrote:
>>
>>> Hello mailto:golang-codereviews@googlegroups.com (cc: adonovan, iant,
>>>
>> khr, r),
>>
>>  I'd like you to review this change to
>>> https://code.google.com/p/go/
>>>
>>
>> Thanks Russ.
>>
>> Do we have any benchmarks that exercise hash table performance and that
>> might have caught this, or could be easily extended to do so?
>
>
> test/mapnan.go might be a start.
>

[rsc, 2014-08-06 20:22:55]

*** Submitted as https://code.google.com/p/go/source/detail?r=fc7539d17fd7 ***

runtime: use better hash for non-empty interface

The implementation 'return 0' results in too many collisions.

LGTM=khr
R=golang-codereviews, adonovan, khr
CC=golang-codereviews, iant, khr, r
https://codereview.appspot.com/125720044

[bradfitz, 2014-08-07 04:50:29]

Thanks. My personal Camlistore server can start up again.

Before this, trying to add 1.5M interface values to a map didn't make it
very far.  :)



On Wed, Aug 6, 2014 at 1:22 PM, <rsc@golang.org> wrote:

> *** Submitted as
> https://code.google.com/p/go/source/detail?r=fc7539d17fd7 ***
>
>
> runtime: use better hash for non-empty interface
>
> The implementation 'return 0' results in too many collisions.
>
> LGTM=khr
> R=golang-codereviews, adonovan, khr
> CC=golang-codereviews, iant, khr, r
> https://codereview.appspot.com/125720044
>
>
> https://codereview.appspot.com/125720044/
>
>
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