On Mon, 2 Nov 2015 12:22:47 +0000
"Hunt, David" <david.hunt at intel.com> wrote:
> On 02/11/2015 04:57, Jerin Jacob wrote:
> > On Fri, Oct 30, 2015 at 01:49:14PM +0000, David Hunt wrote:
> >> Signed-off-by: David Hunt <david.hunt at intel.com>
> --snip--
> >> +#ifndef _RTE_MEMCPY_ARM_64_H_
> >> +#define _RTE_MEMCPY_ARM_64_H_
> >> +
> >> +#include <stdint.h>
> >> +#include <string.h>
> >> +
> >> +#ifdef __cplusplus
> >> +extern "C" {
> >> +#endif
> >> +
> >> +#include "generic/rte_memcpy.h"
> >> +
> >> +#ifdef __ARM_NEON_FP
> >
> > SIMD is not optional in armv8 spec.So every armv8 machine will have
> > SIMD instruction unlike armv7.More over LDP/STP instruction is
> > not part of SIMD.So this check is not required or it can
> > be replaced with a check that select memcpy from either libc or this
> > specific
> > implementation
>
> Jerin,
> I've just benchmarked the libc version against the hand-coded
> version of the memcpy routines, and the libc wins in most cases. This
> code was just an initial attempt at optimising the memccpy's, so I feel
> that with the current benchmark results, it would better just to remove
> the assembly versions, and use the libc version for the initial release
> on ARMv8.
> Then, in the future, the ARMv8 experts are free to submit an optimised
> version as a patch in the future. Does that sound reasonable to you?
> Rgds,
> Dave.
As there is no use of NEON in the code, this optimization seems to be
useless to me...
Jan
>
>
> --snip--
>
>
>
--
Jan Viktorin E-mail: Viktorin at RehiveTech.com
System Architect Web: www.RehiveTech.com
RehiveTech
Brno, Czech Republic
