code review 84750047: net: fix data race in benchmark

net: fix data race in benchmark
If an error happens on a connection, server goroutine can call b.Logf
after benchmark finishes.
So join both client and server goroutines.
Update issue 7718

[dvyukov, 2014-04-07 06:42:00]

Hello golang-codereviews@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go/

[bradfitz, 2014-04-07 06:48:51]

LGTM
 On Apr 6, 2014 11:42 PM, <dvyukov@google.com> wrote:

> Reviewers: golang-codereviews,
>
> Message:
> Hello golang-codereviews@googlegroups.com,
>
> I'd like you to review this change to
> https://dvyukov%40google.com@code.google.com/p/go/
>
>
> Description:
> net: fix data race in benchmark
> If an error happens on a connection, server goroutine can call b.Logf
> after benchmark finishes.
> So join both client and server goroutines.
> Update issue 7718
>
> Please review this at https://codereview.appspot.com/84750047/
>
> Affected files (+12, -6 lines):
>   M src/pkg/net/tcp_test.go
>
>
> Index: src/pkg/net/tcp_test.go
> ===================================================================
> --- a/src/pkg/net/tcp_test.go
> +++ b/src/pkg/net/tcp_test.go
> @@ -97,6 +97,7 @@
>                 b.Fatalf("Listen failed: %v", err)
>         }
>         defer ln.Close()
> +       serverSem := make(chan bool, numConcurrent)
>         // Acceptor.
>         go func() {
>                 for {
> @@ -104,9 +105,13 @@
>                         if err != nil {
>                                 break
>                         }
> +                       serverSem <- true
>                         // Server connection.
>                         go func(c Conn) {
> -                               defer c.Close()
> +                               defer func() {
> +                                       c.Close()
> +                                       <-serverSem
> +                               }()
>                                 if timeout {
>                                        
c.SetDeadline(time.Now().Add(time.Hour))
> // Not intended to fire.
>                                 }
> @@ -119,13 +124,13 @@
>                         }(c)
>                 }
>         }()
> -       sem := make(chan bool, numConcurrent)
> +       clientSem := make(chan bool, numConcurrent)
>         for i := 0; i < conns; i++ {
> -               sem <- true
> +               clientSem <- true
>                 // Client connection.
>                 go func() {
>                         defer func() {
> -                               <-sem
> +                               <-clientSem
>                         }()
>                         c, err := Dial("tcp", ln.Addr().String())
>                         if err != nil {
> @@ -144,8 +149,9 @@
>                         }
>                 }()
>         }
> -       for i := 0; i < cap(sem); i++ {
> -               sem <- true
> +       for i := 0; i < numConcurrent; i++ {
> +               clientSem <- true
> +               serverSem <- true
>         }
>  }
>
>
>
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[dvyukov, 2014-04-07 07:00:11]

*** Submitted as https://code.google.com/p/go/source/detail?r=45241e8ac3d6 ***

net: fix data race in benchmark
If an error happens on a connection, server goroutine can call b.Logf
after benchmark finishes.
So join both client and server goroutines.
Update issue 7718

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/84750047

[gobot, 2014-04-07 07:33:22]

This CL appears to have broken the darwin-amd64-race-cheney builder.
See http://build.golang.org/log/13bfd590fedca3a35b5671347d06d5fd35d3848b