[Mesa-dev] [PATCH] gallium/os: use CLOCK_MONOTONIC for sleeps

[Eric Engestrom]

On Mon, Jul 18, 2016 at 02:14:49PM +0200, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> ---
>  src/gallium/auxiliary/os/os_time.c | 15 +++++++++++++--
>  src/gallium/auxiliary/os/os_time.h |  4 ----
>  2 files changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/src/gallium/auxiliary/os/os_time.c b/src/gallium/auxiliary/os/os_time.c
> index 3d2e416..633ee3d 100644
> --- a/src/gallium/auxiliary/os/os_time.c
> +++ b/src/gallium/auxiliary/os/os_time.c
> @@ -81,19 +81,30 @@ os_time_get_nano(void)
>  }
>  
>  
> -#if defined(PIPE_SUBSYSTEM_WINDOWS_USER)
>  
>  void
>  os_time_sleep(int64_t usecs)
>  {
> +#if defined(PIPE_OS_LINUX)
> +   struct timespec time; \
> +   time.tv_sec = usecs / 1000000; \
> +   time.tv_nsec = (usecs % 1000000) * 1000; \
> +   clock_nanosleep(CLOCK_MONOTONIC, 0, &time, NULL); \

This is an actual function, not a macro; the backslashes are unnecessary :)
This is a good change though, so with those removed:
Reviewed-by: Eric Engestrom <eric.engestrom at imgtec.com>

One (kind of unrelated) thing, though:
Does a negative sleep really make sense? Shouldn't the param be `uint64_t`?
I know on Linux and Unix it doesn't.
If there a reason to keep it signed, maybe a check like this could be
added:
	if (usecs < 0) return;

(That'd be a separate patch anyway)

> +
> +#elif defined(PIPE_OS_UNIX)
> +   usleep(usecs);
> +
> +#elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
>     DWORD dwMilliseconds = (DWORD) ((usecs + 999) / 1000);
>     /* Avoid Sleep(O) as that would cause to sleep for an undetermined duration */
>     if (dwMilliseconds) {
>        Sleep(dwMilliseconds);
>     }
> +#else
> +#  error Unsupported OS
> +#endif
>  }
>  
> -#endif
>  
>  
>  int64_t
> diff --git a/src/gallium/auxiliary/os/os_time.h b/src/gallium/auxiliary/os/os_time.h
> index 9312e02..ca0bdd5 100644
> --- a/src/gallium/auxiliary/os/os_time.h
> +++ b/src/gallium/auxiliary/os/os_time.h
> @@ -70,12 +70,8 @@ os_time_get(void)
>  /*
>   * Sleep.
>   */
> -#if defined(PIPE_OS_UNIX)
> -#define os_time_sleep(_usecs) usleep(_usecs)
> -#else
>  void
>  os_time_sleep(int64_t usecs);
> -#endif
>  
>  
>  /*
> -- 
> 2.7.4