Re: [Qemu-devel] [PATCH] Add configure clock_gettime() monotonic time test

[Paolo Bonzini <pbonzini@redhat.com>]

Il 02/04/2013 17:42, Brad Smith ha scritto:
> Replace the hardcoded list of OS's utilizing clock_gettime() for monotonic
> time with a configure test. This is to fix the use of monotonic time on
> OpenBSD but allows for other POSIX compliant OS's such as NetBSD to also
> utilize clock_gettime().

I thought the list of OSes was supposed to filter out those that somehow
had a broken CLOCK_MONOTONIC.

Otherwise, you might as well use "#ifdef CLOCK_MONOTONIC" and skip the
configure test completely.

Paolo

> 
> Signed-off-by: Brad Smith <brad@comstyle.com>
> 
> diff --git a/configure b/configure
> index fbea75e..352d6a6 100755
> --- a/configure
> +++ b/configure
> @@ -2896,6 +2896,21 @@ if test "$darwin" != "yes" -a "$mingw32" != "yes" -a "$solaris" != yes -a \
>  fi
>  
>  ##########################################
> +# clock_gettime() probe, used for monotonic time
> +clock_monotonic="no"
> +cat > $TMPC << EOF
> +#include <time.h>
> +int main(void)
> +{
> +    clock_gettime(CLOCK_MONOTONIC, NULL);
> +    return 0;  
> +}   
> +EOF
> +if compile_prog "" "" ; then
> +   clock_monotonic="yes"
> +fi
> +
> +##########################################
>  # spice probe
>  if test "$spice" != "no" ; then
>    cat > $TMPC << EOF
> @@ -3671,6 +3686,9 @@ fi
>  if test "$bswap_h" = "yes" ; then
>    echo "CONFIG_MACHINE_BSWAP_H=y" >> $config_host_mak
>  fi
> +if test "$clock_monotonic" = "yes" ; then
> +  echo "CONFIG_CLOCK_MONOTONIC=y" >> $config_host_mak
> +fi
>  if test "$curl" = "yes" ; then
>    echo "CONFIG_CURL=y" >> $config_host_mak
>    echo "CURL_CFLAGS=$curl_cflags" >> $config_host_mak
> diff --git a/include/qemu/timer.h b/include/qemu/timer.h
> index 1766b2d..d87dfa4 100644
> --- a/include/qemu/timer.h
> +++ b/include/qemu/timer.h
> @@ -117,8 +117,7 @@ extern int use_rt_clock;
>  
>  static inline int64_t get_clock(void)
>  {
> -#if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD_version >= 500000) \
> -    || defined(__DragonFly__) || defined(__FreeBSD_kernel__)
> +#ifdef CONFIG_CLOCK_MONOTONIC
>      if (use_rt_clock) {
>          struct timespec ts;
>          clock_gettime(CLOCK_MONOTONIC, &ts);
> diff --git a/util/qemu-timer-common.c b/util/qemu-timer-common.c
> index 16f5e75..1506942 100644
> --- a/util/qemu-timer-common.c
> +++ b/util/qemu-timer-common.c
> @@ -49,9 +49,7 @@ int use_rt_clock;
>  static void __attribute__((constructor)) init_get_clock(void)
>  {
>      use_rt_clock = 0;
> -#if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD_version >= 500000) \
> -    || defined(__DragonFly__) || defined(__FreeBSD_kernel__) \
> -    || defined(__OpenBSD__)
> +#ifdef CONFIG_CLOCK_MONOTONIC
>      {
>          struct timespec ts;
>          if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
>