[ltt-dev] [PATCH] Remove PowerPC specific time reading function

[Mathieu Desnoyers]

* Yannick Brosseau (yannick.brosseau at gmail.com) wrote:
> The PPC version of the trace_clock_read64 was using the TB register
> which is not constant accross implementations. The currently
> measured time base on PPC was not accurate.
> So, for now, we rely on the CLOCK_MONOTONIC.
> 
> This patch remove a bunch of #ifdef for x86 and PPC, since we now rely on
> the same base clock. It also fix the build on PPC that was currently broken

Merged, thanks !

We should do a 0.12 bugfix release soon. This is a major showstopper on
ppc.

Mathieu

> 
> Signed-off-by: Yannick Brosseau <yannick.brosseau at gmail.com>
> ---
>  include/ust/clock.h |   30 ++----------------------------
>  1 files changed, 2 insertions(+), 28 deletions(-)
> 
> diff --git a/include/ust/clock.h b/include/ust/clock.h
> index 04785fc..5e558f8 100644
> --- a/include/ust/clock.h
> +++ b/include/ust/clock.h
> @@ -39,7 +39,6 @@
>     precision and monotonicity.
>  */
>  
> -#if __i386__ || __x86_64__
>  /* Only available for x86 arch */
>  #define CLOCK_TRACE_FREQ  14
>  #define CLOCK_TRACE  15
> @@ -47,36 +46,10 @@ union lttng_timespec {
>  	struct timespec ts;
>  	u64 lttng_ts;
>  };
> -#endif /* __i386__ || __x86_64__ */
>  
>  extern int ust_clock_source;
>  
>  /* Choosing correct trace clock */
> -#if __PPC__
> -static __inline__ u64 trace_clock_read64(void)
> -{
> -	unsigned long tb_l;
> -	unsigned long tb_h;
> -	unsigned long tb_h2;
> -	u64 tb;
> -
> -	__asm__ (
> -		"1:\n\t"
> -		"mftbu %[rhigh]\n\t"
> -		"mftb %[rlow]\n\t"
> -		"mftbu %[rhigh2]\n\t"
> -		"cmpw %[rhigh],%[rhigh2]\n\t"
> -		"bne 1b\n\t"
> -		: [rhigh] "=r" (tb_h), [rhigh2] "=r" (tb_h2), [rlow] "=r" (tb_l));
> -
> -	tb = tb_h;
> -	tb <<= 32;
> -	tb |= tb_l;
> -
> -	return tb;
> -}
> -
> -#else	/* !__PPC__ */
>  
>  static __inline__ u64 trace_clock_read64(void)
>  {
> @@ -101,17 +74,18 @@ static __inline__ u64 trace_clock_read64(void)
>  	return retval;
>  }
>  
> -#endif /* __PPC__ */
>  
>  static __inline__ u64 trace_clock_frequency(void)
>  {
>  	struct timespec ts;
>  	union lttng_timespec *lts = (union lttng_timespec *) &ts;
>  
> +#if __i386__ || __x86_64__
>  	if (likely(ust_clock_source == CLOCK_TRACE)) {
>  		clock_gettime(CLOCK_TRACE_FREQ, &ts);
>  		return lts->lttng_ts;
>  	}
> +#endif
>  	return 1000000000LL;
>  }
>  
> -- 
> 1.7.2.3
> 
> 
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> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com