From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Hunt, David" <david.hunt@intel.com>
Subject: Re: [PATCH v3 1/6] eal/arm: add 64-bit armv8 version of
 rte_memcpy.h
Date: Mon, 2 Nov 2015 12:22:47 +0000
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To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
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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@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.


--snip--