code review 6070043: runtime: add benchmark for complex128 division

runtime: add benchmark for complex128 division

[chaten, 2012-04-19 06:02:27]

Hello golang-dev@googlegroups.com (cc: minux.ma@gmail.com),

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

[dave_cheney.net, 2012-04-19 06:42:29]

LGTM. Have you filled in a CLA ?

On Thu, Apr 19, 2012 at 4:02 PM,  <mchaten@gmail.com> wrote:
> Reviewers: golang-dev_googlegroups.com,
>
> Message:
> Hello golang-dev@googlegroups.com (cc: minux.ma@gmail.com),
>
> I'd like you to review this change to
> https://code.google.com/p/go/
>
>
> Description:
> runtime: add benchmark for complex128 division
>
> Please review this at http://codereview.appspot.com/6070043/
>
> Affected files:
>  A src/pkg/runtime/complex_test.go
>
>
> Index: src/pkg/runtime/complex_test.go
> ===================================================================
> new file mode 100644
> --- /dev/null
> +++ b/src/pkg/runtime/complex_test.go
> @@ -0,0 +1,52 @@
> +// Copyright 2012 The Go Authors. All rights reserved.
> +// Use of this source code is governed by a BSD-style
> +// license that can be found in the LICENSE file.
> +
> +package runtime_test
> +
> +import (
> +       "math/cmplx"
> +       "testing"
> +)
> +
> +var result complex128
> +
> +func BenchmarkComplex128DivNormal(b *testing.B) {
> +       d := 15 + 2i
> +       n := 32 + 3i
> +       for i := 0; i < b.N; i++ {
> +               result = n / d
> +       }
> +}
> +
> +func BenchmarkComplex128DivNisNaN(b *testing.B) {
> +       d := cmplx.NaN()
> +       n := 32 + 3i
> +       for i := 0; i < b.N; i++ {
> +               result = n / d
> +       }
> +}
> +
> +func BenchmarkComplex128DivDisNaN(b *testing.B) {
> +       d := 15 + 2i
> +       n := cmplx.NaN()
> +       for i := 0; i < b.N; i++ {
> +               result = n / d
> +       }
> +}
> +
> +func BenchmarkComplex128DivNisInf(b *testing.B) {
> +       d := 15 + 2i
> +       n := cmplx.Inf()
> +       for i := 0; i < b.N; i++ {
> +               result = n / d
> +       }
> +}
> +
> +func BenchmarkComplex128DivDisInf(b *testing.B) {
> +       d := cmplx.Inf()
> +       n := 32 + 3i
> +       for i := 0; i < b.N; i++ {
> +               result = n / d
> +       }
> +}
>
>

[chaten, 2012-04-19 16:05:35]

Yes
On 2012/04/19 06:42:29, dfc wrote:
> LGTM. Have you filled in a CLA ?
> 
> On Thu, Apr 19, 2012 at 4:02 PM,  <mailto:mchaten@gmail.com> wrote:
> > Reviewers: http://golang-dev_googlegroups.com,
> >
> > Message:
> > Hello mailto:golang-dev@googlegroups.com (cc: mailto:minux.ma@gmail.com),
> >
> > I'd like you to review this change to
> > https://code.google.com/p/go/
> >
> >
> > Description:
> > runtime: add benchmark for complex128 division
> >
> > Please review this at http://codereview.appspot.com/6070043/
> >
> > Affected files:
> > &nbsp;A src/pkg/runtime/complex_test.go
> >
> >
> > Index: src/pkg/runtime/complex_test.go
> > ===================================================================
> > new file mode 100644
> > --- /dev/null
> > +++ b/src/pkg/runtime/complex_test.go
> > @@ -0,0 +1,52 @@
> > +// Copyright 2012 The Go Authors. All rights reserved.
> > +// Use of this source code is governed by a BSD-style
> > +// license that can be found in the LICENSE file.
> > +
> > +package runtime_test
> > +
> > +import (
> > + &nbsp; &nbsp; &nbsp; "math/cmplx"
> > + &nbsp; &nbsp; &nbsp; "testing"
> > +)
> > +
> > +var result complex128
> > +
> > +func BenchmarkComplex128DivNormal(b *testing.B) {
> > + &nbsp; &nbsp; &nbsp; d := 15 + 2i
> > + &nbsp; &nbsp; &nbsp; n := 32 + 3i
> > + &nbsp; &nbsp; &nbsp; for i := 0; i < b.N; i++ {
> > + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; result = n / d
> > + &nbsp; &nbsp; &nbsp; }
> > +}
> > +
> > +func BenchmarkComplex128DivNisNaN(b *testing.B) {
> > + &nbsp; &nbsp; &nbsp; d := cmplx.NaN()
> > + &nbsp; &nbsp; &nbsp; n := 32 + 3i
> > + &nbsp; &nbsp; &nbsp; for i := 0; i < b.N; i++ {
> > + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; result = n / d
> > + &nbsp; &nbsp; &nbsp; }
> > +}
> > +
> > +func BenchmarkComplex128DivDisNaN(b *testing.B) {
> > + &nbsp; &nbsp; &nbsp; d := 15 + 2i
> > + &nbsp; &nbsp; &nbsp; n := cmplx.NaN()
> > + &nbsp; &nbsp; &nbsp; for i := 0; i < b.N; i++ {
> > + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; result = n / d
> > + &nbsp; &nbsp; &nbsp; }
> > +}
> > +
> > +func BenchmarkComplex128DivNisInf(b *testing.B) {
> > + &nbsp; &nbsp; &nbsp; d := 15 + 2i
> > + &nbsp; &nbsp; &nbsp; n := cmplx.Inf()
> > + &nbsp; &nbsp; &nbsp; for i := 0; i < b.N; i++ {
> > + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; result = n / d
> > + &nbsp; &nbsp; &nbsp; }
> > +}
> > +
> > +func BenchmarkComplex128DivDisInf(b *testing.B) {
> > + &nbsp; &nbsp; &nbsp; d := cmplx.Inf()
> > + &nbsp; &nbsp; &nbsp; n := 32 + 3i
> > + &nbsp; &nbsp; &nbsp; for i := 0; i < b.N; i++ {
> > + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; result = n / d
> > + &nbsp; &nbsp; &nbsp; }
> > +}
> >
> >

[dave_cheney.net, 2012-04-21 01:21:48]

If there are no objections, I will submit this later today.

[rsc, 2012-04-21 02:02:50]

LGTM

{
n += n/d
}
result = n

might work a little better for avoiding optimizations.
i bet gccgo compiles the loop away.

[dave_cheney.net, 2012-04-21 03:24:56]

*** Submitted as http://code.google.com/p/go/source/detail?r=53bde4a93e92 ***

runtime: add benchmark for complex128 division

R=golang-dev, dave, rsc
CC=golang-dev, minux.ma
http://codereview.appspot.com/6070043

Committer: Dave Cheney <dave@cheney.net>

[dave_cheney.net, 2012-04-21 03:27:05]

> might work a little better for avoiding optimizations.
> i bet gccgo compiles the loop away.

Thanks Russ. I made your suggested change. There was no significant change in
the benchmark results using this form.