Hi,
On 24/04/2025 4:31 PM, Viacheslav Ovsiienko wrote:
he DPDK API rte_eth_tx_queue_setup() has a parameter nb_tx_desc
specifying the desired queue capacity, measured in packets.
The ConnectX NIC series has a hardware-imposed queue size
limit of 32K WQEs (packet hardware descriptors). Typically,
one packet requires one WQE to be sent.
There is a special offload option, data-inlining, to improve
performance for small packets. Also, NICs in some configurations
require a minimum amount of inline data for the steering engine
to operate correctly.
In the case of inline data, more than one WQEs might be required
to send a single packet. The mlx5 PMD takes this into account
and adjusts the number of queue WQEs accordingly.
If the requested queue capacity can't be satisfied due to
the hardware queue size limit, the mlx5 PMD rejected the queue
creation, causing unresolvable application failure.
The patch provides the following:
- fixes the calculation of the number of required WQEs
to send a single packet with inline data, making it more precise
and extending the painless operating range.
- If the requested queue capacity can't be satisfied due to WQE
number adjustment for inline data, it no longer causes a severe
error. Instead, a warning message is emitted, and the queue
is created with the maximum available size, with a reported success.
Please note that the inline data size depends on many options
(NIC configuration, queue offload flags, packet offload flags,
packet size, etc.), so the actual queue capacity might not be
impacted at all.
Signed-off-by: Viacheslav Ovsiienko <viachesl...@nvidia.com>
Acked-by: Dariusz Sosnowski <dsosnow...@nvidia.com>
Patch applied to next-net-mlx,
--
Kindest regards
Raslan Darawsheh
