[dpdk-dev] [PATCH v2] mbuf:rearrange mbuf to be more mbuf chain friendly

Wiles, Keith keith.wiles at intel.com
Mon Jun 27 15:06:11 CEST 2016

On 6/27/16, 4:05 AM, "Thomas Monjalon" <thomas.monjalon at 6wind.com> wrote:

>2016-06-27 10:27, Olivier Matz:
>> On 06/27/2016 10:21 AM, Ananyev, Konstantin wrote:
>> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Keith Wiles
>> >> Move the next pointer to the first cacheline of the rte_mbuf structure
>> >> and move the offload values to the second cacheline to give better
>> >> performance to applications using chained mbufs.
>> >>
>> >> Enabled by a configuration option CONFIG_RTE_MBUF_CHAIN_FRIENDLY default
>> >> is set to No.
>> > 
>> > First, it would make ixgbe and i40e vector RX functions to work incorrectly.
>> > Second, I don't think we can afford to allow people swap mbuf fields in the way they like.
>> > Otherwise we'll end-up with totally unmaintainable code pretty soon.
>> > So NACK.  
>> +1
>To be more precise, the arrangement of fields in rte_mbuf is open
>to debate and changes.
>There is a recent discussion here:
>	http://dpdk.org/ml/archives/dev/2016-May/039483.html
>I think we must try to improve few things in mbuf during the 16.11 cycle.
>But it must not be allowed to have a build option to adapt this structure
>or any other API. There is only one DPDK API for a given version.

I just received a private email thread on this one and it appears it is not a big of a problem as was stated before. ☹ So yes we can reject this one.

Someone rejected these in patchwork already, which I expected I would be the one to reject the patches. Is this not the case? I understand if the patch just hangs round, but I would have expected after the list rejected the patch I would be the one to reject the patches. I try to keep up with my patches and rejecting a patch before I have a chance to do so seems a bit harsh to me.


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