Re: [dpdk-dev] [PATCH 1/2] net/qede: fix ovs-dpdk failure when using odd number of queues on 100Gb mode

[Jerin Jacob Kollanukkaran <jerinj@marvell.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Shahed Shaikh
> Sent: Wednesday, September 4, 2019 5:01 PM
> To: dev@dpdk.org
> Cc: Rasesh Mody <rmody@marvell.com>; ferruh.yigit@intel.com; GR-
> Everest-DPDK-Dev <GR-Everest-DPDK-Dev@marvell.com>; stable@dpdk.org
> Subject: [dpdk-dev] [PATCH 1/2] net/qede: fix ovs-dpdk failure when using
> odd number of queues on 100Gb mode
> 
> As per HW design of 100Gb mode, device internally uses 2 engines
> (eng0 and eng1), and both engines need to be configured symmetrically.
> Based on this requirement, driver design chose an approach to allow user to
> allocate only even number of queues and split those queues on both engines
> equally.
> 
> This approach puts a limitation on number of queues to be allocated - i.e.
> user can't configure odd number of queues on 100Gb mode.
> OVS configures DPDK port with 1 rxq and 1 txq, which causes initialization of
> qede port to fail.
> 
> This patch changes the implementation of queue allocation method for
> 100Gb devices by removing above mentioned limitation and allowing user to
> configure odd number of queues.
> 
> Key changes in this patch -
>  - Allocate requested queue count on both engines, so that
>    actual hardware queue count will be double of what user requested.
>  - Create a pair of queues from both engines and provide it to
>    rte_ethdev queue structure. So ethdev will see only one queue for
>    underlying queue pair created for hw engine pair.
>  - Rx and Tx methods from ethdev will provide that queue pair
>    object and PMD will internally split Rx and Tx packet processing across
>    both engines in separately installed Rx and Tx handlers.
>  - Consolidate statistics of both HW queues while reporting to application.
>  - Report engine wise queue statistics in xstats flow.
>    e.g. - rx_q<hw_eng_id>.<qid>_xxxxxxx


Multiple logical changes in one patch. Please split the patch to more
logical ones for easy review.



> 
> Fixes: 2af14ca79c0a ("net/qede: support 100G")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Shahed Shaikh <shshaikh@marvell.com>