From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ferruh Yigit <ferruh.yigit@intel.com>
Subject: Re: [RFC] ethdev: add new offload flag to keep CRC
Date: Mon, 11 Jun 2018 10:18:18 +0100
Message-ID: <ee81b2ec-654b-2eff-6468-f79d4e974caf@intel.com>
References: <20180608225709.19473-1-ferruh.yigit@intel.com>
 <75ca3e7f-9241-309f-c2ce-5c01f65bfdf9@solarflare.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Cc: dev@dpdk.org
To: Andrew Rybchenko <arybchenko@solarflare.com>,
 Neil Horman <nhorman@tuxdriver.com>, John McNamara
 <john.mcnamara@intel.com>, Marko Kovacevic <marko.kovacevic@intel.com>,
 Thomas Monjalon <thomas@monjalon.net>
Return-path: <dev-bounces@dpdk.org>
Received: from mga17.intel.com (mga17.intel.com [192.55.52.151])
 by dpdk.org (Postfix) with ESMTP id D16061E875
 for <dev@dpdk.org>; Mon, 11 Jun 2018 11:18:21 +0200 (CEST)
In-Reply-To: <75ca3e7f-9241-309f-c2ce-5c01f65bfdf9@solarflare.com>
Content-Language: en-US
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://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: <https://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 6/9/2018 11:11 AM, Andrew Rybchenko wrote:
> On 06/09/2018 01:57 AM, Ferruh Yigit wrote:
>> DEV_RX_OFFLOAD_KEEP_CRC offload flag added.
>>
>> DEV_RX_OFFLOAD_CRC_STRIP flag will remain one more release
>> default behavior in PMDs is to keep the CRC until this flag removed
>>
>> Until DEV_RX_OFFLOAD_CRC_STRIP flag is removed:
>> - Setting both KEEP_CRC & CRC_STRIP is INVALID
> 
> ethdev layer should enforce it.

OK, will add this check.

> 
>> - Setting only CRC_STRIP PMD should strip the CRC
>> - Setting only KEEP_CRC PMD should keep the CRC
>> - Not setting both PMD should keep the CRC
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 
> - rte_rx_offload_names should be updated as well
> - testpmd should be updated
> 
> I'm not sure that I understand the transition plan. I think PMDs which support
> KEEP_CRC should be updated by the patch to advertise the offload. Otherwise,
> generic checks in ethdev will not allow to enable it. 

Right, PMDs should be updated to advertise this offload, will do it.

> Other option is to simply
> drop it on ethdev layer (since basically it changes nothing for PMD now) and
> encourage PMD maintainers to advertise and take it into account if the feature
> is supported (however, if the bit is dropped on ethdev layer, the code would
> be unused/dead regardless application request). Too complicated. I guess
> there are not so many PMDs which support KEEP_CRC. Better to update them

> The patch should encourage applications which would like to keep CRC to
> use the offload since the next release will drop CRC_STRIP and it will
> change behaviour (no KEEP_CRC => strip it)

+1, will check apps.