[dpdk-users] Attaching to an ethernet port from a secondary process

Lazaros Koromilas l at nofutznetworks.com
Fri Feb 19 17:22:00 CET 2016

Thanks for your reply Reshma, that clears things up.


On Fri, Feb 19, 2016 at 2:58 PM, Pattan, Reshma <reshma.pattan at intel.com> wrote:
> Hi,
>> -----Original Message-----
>> From: users [mailto:users-bounces at dpdk.org] On Behalf Of Lazaros Koromilas
>> Sent: Wednesday, February 17, 2016 11:40 AM
>> To: users at dpdk.org
>> Subject: Re: [dpdk-users] Attaching to an ethernet port from a secondary
>> process
>> On Wed, Feb 17, 2016 at 1:17 PM, Lazaros Koromilas <l at nofutznetworks.com>
>> wrote:
>> > Hi all,
>> >
>> > I'm trying to take advantage of the multi-process support together
>> > with the port hotplugging framework. The idea is that my primary
>> > process will configure all ports I'm going to need and then secondary
>> > processes will come up, selectively attach to ports and perform rx/tx.
> From quick glance of dpdk code what I see is  rte_eth_dev_attach  will  not attach existing port to DPDK app.
> Because from "librte_ether/rte_ethdev.c" rte_eth_dev_attach()==> rte_eth_dev_attach_vdev()==>rte_eal_vdev_init() creates new vdev and returns you the port id.
> And moreover vdevs are local to process.
> You may have to check clearly what is the hot plug functionality and do you really need it in your case.
>> > Where pcap{0,1}-in.pcap files are pcap dumps. The primary will
>> > initialize the ports and pause(2). The secondary will attach to the
>> > same ports and do work. The latter then segfaults in
>> > rte_eth_rx_burst() with dev->data->{rx,tx}_queues being NULL pointers.
>> >
> Since in secondary  new device is created, but device configuration and queue configuration  is not done,  crash is expected.
> Thanks,
> Reshma

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