Hello

Stephen, thanks for your answer.

>Which of the rte_eth_xxx functions are you asking about?

I wonder if the following rte_eth_xxx functions can be used in secondary processes:

rte_eth_rx_burst

rte_eth_tx_burst

rte_eth_stats_reset

rte_eth_xstats_get

rte_eth_rx_queue_setup

rte_eth_tx_queue_setup

rte_eth_macaddr_getueue_setup

rte_eth_dev_set_mtu

rte_eth_dev_rx_queue_stop

rte_eth_dev_tx_queue_stop

rte_eth_dev_info_get

rte_eth_dev_get_name_by_port

rte_eth_dev_start

rte_eth_dev_socket_id

rte_eth_dev_configure

rte_eth_dev_count_avail

I also would like to ask if a secondary process can create and free memory pools using for example the following functions:

rte_pktmbuf_pool_create

rte_mempool_create

rte_mempool_create_empty

rte_mempool_set_ops_byname

rte_mempool_populate_default

rte_mempool_free

The applications I would like to use for shared memory using the DPDK multi-process use these rte_eth_xxx and rte memory pool functions for handling

Ethernet devices and memory pools so I wonder if these applications need to be modified in order to be used as secondary processes.

The NICs I plan to use are Intel 700 series (XL710 40GbE, XXV710 25 GbE) and Mellanox ConnectX-4 Lx 25GbE, ConnectX-5 100 GbE and ConnectX-6 100 GbE.

Can these be used from both the primary and the secondary processes?

Regards

Staffan

Den fre 26 nov. 2021 kl 18:22 skrev Stephen Hemminger <stephen@networkplumber.org>:

On Fri, 26 Nov 2021 13:27:40 +0100
Staffan Wiklund <staffan491@gmail.com> wrote:

> Hello
>
> I wonder if you please can help me with some questions regarding the DPDK
> multi-process feature?
>
> If a primary process and the secondary processes all execute on different
> CPU cores,
> what limitations are there on the secondary processes when using DPDK
> functions
> for initialization of EAL and for handling ethernet devices?
>
> That is, is a secondary process allowed to call the rte_eal_init function
> or any of
> the rte_eth_xxx functions?

Secondary process has to call rte_eal_init() with secondary (or auto flag).
Which of the rte_eth_xxx functions are you asking about?

> What will happen if a secondary process calls any of these DPDK functions?
>
> The reason for these questions is that I would like to execute 3-4 DPDK
> applications that
> now executes as stand-alone applications as one primary process and the
> other
> applications as secondary processes. All these processes will share memory
> which
> shall be used to improve the speed of communication between the
> applications.

Several applications do this.

> The applications currently use DPDK for Ethernet based communication and I
> would
> like to learn what needs to be modified in order to be able to execute them
> as a
> primary and secondary processes using DPDK shared memory.
>
> Best regards
> Staffan

To be honest, my experience is that not all functions work on all drivers
with the multi-process model. The documentation mostly covers the ones that
don't but you have to be careful and test with particular drivers and use cases.