[dpdk-dev] Aligned RX data.

[Ananyev, Konstantin]

> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Tuesday, October 07, 2014 5:03 PM
> To: Ananyev, Konstantin
> Subject: FW: [dpdk-dev] Aligned RX data.
> 
> 
> 
> From: Alex Markuze [mailto:alex at weka.io]
> Sent: Tuesday, October 07, 2014 4:52 PM
> To: Ananyev, Konstantin
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] Aligned RX data.
> 
> RTE_PKTMBUF_HEADROOM defines the headroom

Yes.

>this would be true only if the buff_start was aligned to 512 which is not.

As I said: " Make sure that your all your mbufs are aligned by 512".  

Konstantin

> 
> On Tue, Oct 7, 2014 at 1:05 PM, Ananyev, Konstantin <konstantin.ananyev at intel.com> wrote:
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Alex Markuze
> > Sent: Tuesday, October 07, 2014 10:40 AM
> > To: dev at dpdk.org
> > Subject: [dpdk-dev] Aligned RX data.
> >
> > Hi , I'm trying to receive aligned packets from the wire.
> > Meaning that for all received packets the pkt.data is always aligned to
> > (512 -H).
> >
> > Looking at the pmds of ixgbe/vmxnet I see that the pmds call
> > __rte_mbuf_raw_alloc and set the rx descriptor with a
> > RTE_MBUF_DATA_DMA_ADDR_DEFAULT
> > Instead of the more appropriate RTE_MBUF_DATA_DMA_ADDR.
> >
> > Do I need to modify each pmd I'm using to be able to receive aligned data?
> Make sure that your all your mbufs are aligned by 512 and set in your config RTE_PKTMBUF_HEADROOM=512-H?
> 
> 
> > Or have I missed something?
> >
> > Thanks