code review 6826072: runtime: use vDSO for gettimeofday on linux/amd64

runtime: use vDSO for gettimeofday on linux/amd64

Intel Core 2 Duo (2.16 GHz) running 3.6.5-1-ARCH

benchmark       old ns/op    new ns/op    delta
BenchmarkNow         1856         1034  -44.29%

[ality, 2012-11-08 01:50:34]

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

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

[rsc, 2012-11-08 02:19:17]

LGTM

[ality, 2012-11-08 02:29:39]

*** Submitted as http://code.google.com/p/go/source/detail?r=e3d1b93bfa09 ***

runtime: use vDSO for gettimeofday on linux/amd64

Intel Core 2 Duo (2.16 GHz) running 3.6.5-1-ARCH

benchmark       old ns/op    new ns/op    delta
BenchmarkNow         1856         1034  -44.29%

R=rsc
CC=golang-dev
http://codereview.appspot.com/6826072

[dave_cheney.net, 2012-11-08 02:38:33]

Nice. Is there a similar facility for linux/386 ?

On Thu, Nov 8, 2012 at 1:29 PM,  <ality@pbrane.org> wrote:
> *** Submitted as
> http://code.google.com/p/go/source/detail?r=e3d1b93bfa09 ***
>
>
> runtime: use vDSO for gettimeofday on linux/amd64
>
> Intel Core 2 Duo (2.16 GHz) running 3.6.5-1-ARCH
>
> benchmark       old ns/op    new ns/op    delta
> BenchmarkNow         1856         1034  -44.29%
>
> R=rsc
> CC=golang-dev
> http://codereview.appspot.com/6826072
>
>
> http://codereview.appspot.com/6826072/

[ality, 2012-11-08 03:08:04]

Dave Cheney <dave@cheney.net> once said:
> Nice. Is there a similar facility for linux/386 ?

Nope. The vDSO on linux/386 only supports vsyscalls
and the runtime already uses them if available.

  Anthony

[dave_cheney.net, 2012-11-08 03:09:10]

Fair enough, good to know.

On Thu, Nov 8, 2012 at 2:08 PM, Anthony Martin <ality@pbrane.org> wrote:
> Dave Cheney <dave@cheney.net> once said:
>> Nice. Is there a similar facility for linux/386 ?
>
> Nope. The vDSO on linux/386 only supports vsyscalls
> and the runtime already uses them if available.
>
>   Anthony