code review 68460044: runtime: use monotonic clock for openbsd/386 and openbs...

runtime: use monotonic clock for openbsd/386 and openbsd/amd64 timers

Switch nanotime to a monotonic clock on openbsd/386 and openbsd/amd64.
Also use a monotonic clock when for thrsleep, since the sleep duration
is based on the value returned from nanotime.

Update issue 6007

[jsing, 2014-02-25 15:03:00]

Hello golang-codereviews@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[bradfitz, 2014-02-25 16:24:30]

LGTM

At least read
http://www.openbsd.org/cgi-bin/man.cgi?query=clock_gettime&sektion=2 to
confirm.  And see it's been there since Nov 2003.



On Tue, Feb 25, 2014 at 7:03 AM, <jsing@google.com> wrote:

> Reviewers: golang-codereviews,
>
> Message:
> Hello golang-codereviews@googlegroups.com,
>
> I'd like you to review this change to
> https://go.googlecode.com/hg/
>
>
> Description:
> runtime: use monotonic clock for openbsd/386 and openbsd/amd64 timers
>
> Switch nanotime to a monotonic clock on openbsd/386 and openbsd/amd64.
> Also use a monotonic clock when for thrsleep, since the sleep duration
> is based on the value returned from nanotime.
>
> Update issue 6007
>
> Please review this at https://codereview.appspot.com/68460044/
>
> Affected files (+7, -3 lines):
>   M src/pkg/runtime/os_openbsd.c
>   M src/pkg/runtime/sys_openbsd_386.s
>   M src/pkg/runtime/sys_openbsd_amd64.s
>
>
> Index: src/pkg/runtime/os_openbsd.c
> ===================================================================
> --- a/src/pkg/runtime/os_openbsd.c
> +++ b/src/pkg/runtime/os_openbsd.c
> @@ -82,7 +82,7 @@
>                                 // NOTE: tv_nsec is int64 on amd64, so
> this assumes a little-endian system.
>                                 ts.tv_nsec = 0;
>                                 ts.tv_sec = runtime·timediv(ns,
> 1000000000, (int32*)&ts.tv_nsec);
> -                               runtime·thrsleep(&m->waitsemacount,
> CLOCK_REALTIME, &ts, &m->waitsemalock, nil);
> +                               runtime·thrsleep(&m->waitsemacount,
> CLOCK_MONOTONIC, &ts, &m->waitsemalock, nil);
>                         }
>                         // reacquire lock
>                         while(runtime·xchg(&m->waitsemalock, 1))
> Index: src/pkg/runtime/sys_openbsd_386.s
> ===================================================================
> --- a/src/pkg/runtime/sys_openbsd_386.s
> +++ b/src/pkg/runtime/sys_openbsd_386.s
> @@ -9,6 +9,8 @@
>  #include "zasm_GOOS_GOARCH.h"
>  #include "../../cmd/ld/textflag.h"
>
> +#define        CLOCK_MONOTONIC $3
> +
>  // Exit the entire program (like C exit)
>  TEXT runtime·exit(SB),NOSPLIT,$-4
>         MOVL    $1, AX
> @@ -133,7 +135,7 @@
>  // void nanotime(int64 *nsec)
>  TEXT runtime·nanotime(SB),NOSPLIT,$32
>         LEAL    12(SP), BX
> -       MOVL    $0, 4(SP)               // arg 1 - clock_id
> +       MOVL    CLOCK_MONOTONIC, 4(SP)  // arg 1 - clock_id
>         MOVL    BX, 8(SP)               // arg 2 - tp
>         MOVL    $87, AX                 // sys_clock_gettime
>         INT     $0x80
> Index: src/pkg/runtime/sys_openbsd_amd64.s
> ===================================================================
> --- a/src/pkg/runtime/sys_openbsd_amd64.s
> +++ b/src/pkg/runtime/sys_openbsd_amd64.s
> @@ -9,6 +9,8 @@
>  #include "zasm_GOOS_GOARCH.h"
>  #include "../../cmd/ld/textflag.h"
>
> +#define CLOCK_MONOTONIC        $3
> +
>  // int64 tfork(void *param, uintptr psize, M *mp, G *gp, void
> (*fn)(void));
>  TEXT runtime·tfork(SB),NOSPLIT,$32
>
> @@ -166,7 +168,7 @@
>         RET
>
>  TEXT runtime·nanotime(SB),NOSPLIT,$24
> -       MOVQ    $0, DI                  // arg 1 - clock_id
> +       MOVQ    CLOCK_MONOTONIC, DI     // arg 1 - clock_id
>         LEAQ    8(SP), SI               // arg 2 - tp
>         MOVL    $87, AX                 // sys_clock_gettime
>         SYSCALL
>
>
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[jsing, 2014-02-26 02:20:42]

*** Submitted as https://code.google.com/p/go/source/detail?r=bca0032e86af ***

runtime: use monotonic clock for openbsd/386 and openbsd/amd64 timers

Switch nanotime to a monotonic clock on openbsd/386 and openbsd/amd64.
Also use a monotonic clock when for thrsleep, since the sleep duration
is based on the value returned from nanotime.

Update issue 6007

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/68460044

[gobot, 2014-02-26 02:49:57]

This CL appears to have broken the darwin-386-cheney builder.