[ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime

[pierre-marc.fournier@polymtl.ca (Pierre-Marc Fournier)]

Merged manually because the patch was corrupt. Perhaps due to your user 
agent?

Also modified things to use the full precision.

Thanks!

pmf

Nils Carlson wrote:
> This patch replaces gettimeofday with clock_gettime(CLOCK_MONOTONIC,)
> 
> Signed-off-by: Nils Carlson <nils.carlson at ludd.ltu.se>
> 
> diff --git a/include/ust/clock.h b/include/ust/clock.h
> index d4b6a9d..bc26d26 100644
> --- a/include/ust/clock.h
> +++ b/include/ust/clock.h
> @@ -18,6 +18,7 @@
>  #ifndef UST_CLOCK_H
>  #define UST_CLOCK_H
> 
> +#include <time.h>
>  #include <sys/time.h>
>  #include <ust/kcompat/kcompat.h>
> 
> @@ -25,7 +26,7 @@
> 
>  /* There are two types of clocks that can be used.
>     - TSC based clock
> -   - gettimeofday() clock
> +   - gettimeofday() clock - to guarantee monotonicity use clock_gettime
> 
>     Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are
> inlined):
>       Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
> @@ -41,13 +42,13 @@
> 
>  static __inline__ u64 trace_clock_read64(void)
>  {
> -       struct timeval tv;
> +       struct timespec ts;
>         u64 retval;
> 
> -       gettimeofday(&tv, NULL);
> -       retval = tv.tv_sec;
> +       clock_gettime(CLOCK_MONOTONIC, &ts);
> +       retval = ts.tv_sec;
>         retval *= 1000000;
> -       retval += tv.tv_usec;
> +       retval += ts.tv_nsec / 1000;
> 
>         return retval;
>  }
> diff --git a/libust/Makefile.am b/libust/Makefile.am
> index 2de5857..e357ad1 100644
> --- a/libust/Makefile.am
> +++ b/libust/Makefile.am
> @@ -27,6 +27,7 @@ libust_la_LDFLAGS = -no-undefined -version-info 0:0:0
> 
>  libust_la_LIBADD = \
>         -lpthread \
> +       -lrt \
>         $(top_builddir)/snprintf/libustsnprintf.la \
>         $(top_builddir)/libustcomm/libustcomm.la
> 
> 
> 
> 
> 
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