From: Jerin Jacob <jerin.jacob@caviumnetworks.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 18:27:46 +0530 [thread overview]
Message-ID: <20151102125743.GA9506@localhost.localdomain> (raw)
In-Reply-To: <56375597.8070805@intel.com>
On Mon, Nov 02, 2015 at 12:22:47PM +0000, Hunt, David 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?
Make sense. Based on my understanding, other blocks are also not optimized
for arm64.
So better to revert back to CONFIG_RTE_FORCE_INTRINSICS and
libc for initial version.
BTW: I just tested ./arm64-armv8a-linuxapp-gcc/app/test and
"byteorder_autotest" is broken. I think existing arm64 code is not optimized
beyond CONFIG_RTE_FORCE_INTRINSICS. So better to use verified
CONFIG_RTE_FORCE_INTRINSICS scheme.
if you guys are OK with arm and arm64 as two different platform then
I can summit the complete working patch for arm64.(as in my current source
code "arm64" is a different platform(lib/librte_eal/common/include/arch/arm64/)
> Rgds,
> Dave.
>
>
> --snip--
>
>
>
next prev parent reply other threads:[~2015-11-02 12:58 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
2015-11-02 12:57 ` Jerin Jacob [this message]
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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