From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olivier MATZ <olivier.matz-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum
 offload
Date: Mon, 10 Nov 2014 17:17:22 +0100
Message-ID: <5460E512.1050609@6wind.com>
References: <1414376006-31402-1-git-send-email-jijiang.liu@intel.com>
 <1414376006-31402-11-git-send-email-jijiang.liu@intel.com>
 <54588BF7.309@6wind.com>
 <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8510E@SHSMSX101.ccr.corp.intel.com>
 <5459FBB2.1040408@6wind.com>
 <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8F399@SHSMSX101.ccr.corp.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: "dev-VfR2kkLFssw@public.gmane.org" <dev-VfR2kkLFssw@public.gmane.org>
To: "Liu, Jijiang" <jijiang.liu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Return-path: <dev-bounces-VfR2kkLFssw@public.gmane.org>
In-Reply-To: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8F399-0J0gbvR4kThpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org>
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request-VfR2kkLFssw@public.gmane.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev-VfR2kkLFssw@public.gmane.org>
List-Help: <mailto:dev-request-VfR2kkLFssw@public.gmane.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request-VfR2kkLFssw@public.gmane.org?subject=subscribe>
Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org
Sender: "dev" <dev-bounces-VfR2kkLFssw@public.gmane.org>

Hi Jijiang,

On 11/10/2014 07:03 AM, Liu, Jijiang wrote:
>> Another thing is surprising me.
>>
>> - if PKT_TX_VXLAN_CKSUM is not set (legacy use case), then the
>>    driver use l2_len and l3_len to offload inner IP/UDP/TCP checksums.
> If the flag is not set, and imply that it is not VXLAN packet, 
>  and do TX checksum offload as regular packet.
> 
>> - if PKT_TX_VXLAN_CKSUM is set, then the driver has to use
>>    inner_l{23}_len instead of l{23}_len for the same operation.
> Your understanding is not fully correct.
> The l{23}_len is still used for TX checksum offload, please refer to i40e_txd_enable_checksum()  implementation.

This fields are part of public mbuf API. You cannot say to refer to
i40e PMD code to understand how to use it.

>> Adding PKT_TX_VXLAN_CKSUM changes the semantic of l2_len and l3_len.
>> To fix this, I suggest to remove the new fields inner_l{23}_len then add
>> outer_l{23}_len instead. Therefore, the semantic of l2_len and l3_len would not
>> change, and a driver would always use the same field for a specific offload.
> Oh...

Does it mean you agree?

>> For my TSO development, I will follow the current semantic.
> For TSO, you still can use l{2,3} _len .
> When I develop tunneling TSO, I will use inner_l3_len/inner_l4_len.

I've just submitted a first version, please feel free to comment it.


Regards,
Olivier