From: Jan Viktorin <viktorin@rehivetech.com>
To: "Hunt, David" <david.hunt@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v3 1/6] eal/arm: add 64-bit armv8 version of rte_memcpy.h
Date: Mon, 2 Nov 2015 13:45:57 +0100 [thread overview]
Message-ID: <20151102134557.4bfa593c@pcviktorin.fit.vutbr.cz> (raw)
In-Reply-To: <56375597.8070805@intel.com>
On Mon, 2 Nov 2015 12:22:47 +0000
"Hunt, David" <david.hunt@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@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@RehiveTech.com
System Architect Web: www.RehiveTech.com
RehiveTech
Brno, Czech Republic
next prev parent reply other threads:[~2015-11-02 12:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-30 13:49 [dpdk-dev] [PATCH v3 0/6] ARMv8 additions to ARMv7 support David Hunt
2015-10-30 13:49 ` [dpdk-dev] [PATCH v3 1/6] eal/arm: add 64-bit armv8 version of rte_memcpy.h David Hunt
2015-11-02 4:57 ` Jerin Jacob
2015-11-02 12:22 ` Hunt, David
2015-11-02 12:45 ` Jan Viktorin [this message]
2015-11-02 12:57 ` Jerin Jacob
2015-11-02 15:26 ` Hunt, David
2015-11-02 15:36 ` Jan Viktorin
2015-11-02 15:49 ` Hunt, David
2015-11-02 16:29 ` Jerin Jacob
2015-11-02 17:29 ` Jan Viktorin
2015-10-30 13:49 ` [dpdk-dev] [PATCH v3 2/6] eal/arm: add 64-bit armv8 version of rte_prefetch.h David Hunt
2015-10-30 13:49 ` [dpdk-dev] [PATCH v3 3/6] eal/arm: add 64-bit armv8 version of rte_cycles.h David Hunt
2015-11-02 5:15 ` Jerin Jacob
2015-10-30 13:49 ` [dpdk-dev] [PATCH v3 4/6] eal/arm: fix 64-bit armv8 compilation of rte_cpuflags.h David Hunt
2015-10-30 13:49 ` [dpdk-dev] [PATCH v3 5/6] mk: add support for armv8 on top of armv7 David Hunt
2015-11-02 4:43 ` Jerin Jacob
2015-10-30 13:49 ` [dpdk-dev] [PATCH v3 6/6] test: add checks for cpu flags on armv8 David Hunt
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