From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Viktorin <viktorin@rehivetech.com>
Subject: Re: [PATCH 2/3] arm64: acl: add neon based acl
	implementation
Date: Tue, 3 Nov 2015 11:35:48 +0100
Message-ID: <20151103113548.3c7d4224@jvn>
References: <1446473921-12706-1-git-send-email-jerin.jacob@caviumnetworks.com>
 <1446473921-12706-2-git-send-email-jerin.jacob@caviumnetworks.com>
 <1446473921-12706-3-git-send-email-jerin.jacob@caviumnetworks.com>
 <2601191342CEEE43887BDE71AB97725836AB86A5@irsmsx105.ger.corp.intel.com>
 <20151103043051.GA2228@localhost.localdomain>
 <2601191342CEEE43887BDE71AB97725836AB8AA2@irsmsx105.ger.corp.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Cc: "dev@dpdk.org" <dev@dpdk.org>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from wes1-so1.wedos.net (wes1-so1.wedos.net [46.28.106.15])
 by dpdk.org (Postfix) with ESMTP id A95608E7B
 for <dev@dpdk.org>; Tue,  3 Nov 2015 11:35:56 +0100 (CET)
In-Reply-To: <2601191342CEEE43887BDE71AB97725836AB8AA2@irsmsx105.ger.corp.intel.com>
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On Tue, 3 Nov 2015 10:23:55 +0000
"Ananyev, Konstantin" <konstantin.ananyev@intel.com> wrote:

> > Hi Konstantin,  
> > >
> > > On ARM, is there any specific cpu flag that you can use to determine is NEON
> > > isa is supported or not?  
> > 
> > Yes, on armv7(RTE_CPUFLAG_NEON). On armv8-a NEON is mandatory.
> >   
> > > It would be good to avoid extra conditional compilation here if possible.  
> > neon acl is verified/ported only on armv8. While adding the armv7 support the
> > check can be extended for cpuflag based on RTE_CPUFLAG_NEON on armv7  
> 
> Ok, and is there a flag that allows to distinguish between armv7 and arm8 then at runtime?
> It is probably ok like that, but with all that conditional compilations it gets too messy.
> Another thing - if you can distinguish between armv7 and armv8 at runtime, then you probably
> can set alg = RTE_ACL_CLASSIFY_DEFAULT for armv7 and alg = RTE_ACL_CLASSIFY_NEON for arm8?
> Konstantin

The ARMv7 provides "v7l" in the AT_PLATFORM and the ARMv8 gives
"aarach64". However, I am afraid, as these are two distinct platforms
(with distinct cpuflags), we cannot use the cpuflags easily for this.

Is there an API in DPDK which allows to ask globally: "what platform am
I running on?"?

Jan

> 
> >   
> > > Another question - did I get it right that NEON isa is supported on all
> > > possible RTE_ARCH_ARM64 cpu models you plan to support?  
> > 
> > Yes


-- 
  Jan Viktorin                E-mail: Viktorin@RehiveTech.com
  System Architect            Web:    www.RehiveTech.com
  RehiveTech
  Brno, Czech Republic