[PATCH v2 1/9] eal: use rdtsc intrinsic when compiling with msvc

[Bruce Richardson]

On Tue, Apr 04, 2023 at 01:07:19PM -0700, Tyler Retzlaff wrote:
> Inline assembly is not supported for msvc x64 instead use __rdtsc
> intrinsic.
> 
> Signed-off-by: Tyler Retzlaff <roretzla at linux.microsoft.com>
> ---
>  lib/eal/x86/include/rte_cycles.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/lib/eal/x86/include/rte_cycles.h b/lib/eal/x86/include/rte_cycles.h
> index a461a4d..0c142ce 100644
> --- a/lib/eal/x86/include/rte_cycles.h
> +++ b/lib/eal/x86/include/rte_cycles.h
> @@ -6,6 +6,10 @@
>  #ifndef _RTE_CYCLES_X86_64_H_
>  #define _RTE_CYCLES_X86_64_H_
>  
> +#ifdef RTE_TOOLCHAIN_MSVC
> +#include <intrin.h>
> +#endif
> +
>  #ifdef __cplusplus
>  extern "C" {
>  #endif
> @@ -23,6 +27,7 @@
>  static inline uint64_t
>  rte_rdtsc(void)
>  {
> +#ifndef RTE_TOOLCHAIN_MSVC
>  	union {
>  		uint64_t tsc_64;
>  		RTE_STD_C11
> @@ -47,6 +52,9 @@
>  		     "=a" (tsc.lo_32),
>  		     "=d" (tsc.hi_32));
>  	return tsc.tsc_64;
> +#else
> +	return __rdtsc();
> +#endif
>  }

Checking with google it seems that gcc/clang have an __rdtsc intrinsic as
well, so we may be able to avoid ifdefs here completely.

/Bruce