Re: [dpdk-dev] [PATCH v4] ethdev: add API to query proxy port to manage transfer flows

[Ivan Malov <Ivan.Malov@oktetlabs.ru>]

Hi David,

On 26/10/2021 17:46, David Marchand wrote:
> On Thu, Oct 14, 2021 at 5:22 AM Ivan Malov <ivan.malov@oktetlabs.ru> wrote:
>>
>> Not all DPDK ports in a given switching domain may have the
>> privilege to manage "transfer" flows. Add an API to find a
>> port with sufficient privileges by any port in the domain.
>>
>> Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
>> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>> Acked-by: Ori Kam <orika@nvidia.com>
>> ---
>> Patch series [1] has reworked support for "transfer" flows.
>> This allows to elaborate on the idea which first appeared
>> in RFC [2]. Hence the patch in question.
>>
>> net/sfc driver is going to support the new API. The
>> corresponding patch is already in progress and will
>> be provided in the course of this release cycle.
>>
>> [1] https://patches.dpdk.org/project/dpdk/list/?series=19608
>> [2] https://patches.dpdk.org/project/dpdk/list/?series=18737
>>
> 
> [snip]
> 
>> @@ -568,6 +568,25 @@ eth_rx_metadata_negotiate_mp(uint16_t port_id)
>>          }
>>   }
>>
>> +static void
>> +flow_pick_transfer_proxy_mp(uint16_t port_id)
>> +{
>> +       struct rte_port *port = &ports[port_id];
>> +       int ret;
>> +
>> +       port->flow_transfer_proxy = port_id;
>> +
>> +       if (!is_proc_primary())
>> +               return;
>> +
>> +       ret = rte_flow_pick_transfer_proxy(port_id, &port->flow_transfer_proxy,
>> +                                          NULL);
>> +       if (ret != 0) {
>> +               fprintf(stderr, "Error picking flow transfer proxy for port %u: %s - ignore\n",
>> +                       port_id, rte_strerror(-ret));
>> +       }
>> +}
> 
> I did not follow this subject, but I find it odd to get a warning
> regardless of what is done in testpmd.
> Like simply running a forwarding test with null pmd, I get:

The API is meant to avoid returning error when the PMD does not support
the corresponding method. However, it has to return error when the PMD
does not support flow API at all (rte_flow_ops_get() failure).

I guess, this is exactly what happens in your case. net/null does not
support "flow_ops_get", and the API in question forwards error
from rte_flow_ops_get().

Non-dummy PMDs should not trigger the error you see.

> 
> $ ./devtools/test-null.sh
> EAL: Detected CPU lcores: 8
> EAL: Detected NUMA nodes: 1
> EAL: Detected static linkage of DPDK
> EAL: Multi-process socket /run/user/114840/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'VA'
> Interactive-mode selected
> Auto-start selected
> 
> vvvv
> Error picking flow transfer proxy for port 0: Function not implemented - ignore
> Error picking flow transfer proxy for port 1: Function not implemented - ignore
> ^^^^
> 
> testpmd: create a new mbuf pool <mb_pool_0>: n=2048, size=2176, socket=0
> testpmd: preferred mempool ops selected: ring_mp_mc
> Configuring Port 0 (socket 0)
> Port 0: 12:C9:63:52:5A:8B
> Configuring Port 1 (socket 0)
> Port 1: 92:69:E3:1E:31:82
> Checking link statuses...
> 
> 

-- 
Ivan M