RE: [PATCH 0/2] Add logic to IAVF to count continuous DD bits for Arm

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Kathleen Capella <kathleen.capella@arm.com>
> Sent: Saturday, February 5, 2022 8:26 AM
> Cc: dev@dpdk.org; nd@arm.com; dharmik.thakkar@arm.com;
> honnappa.nagarahalli@arm.com; Kathleen Capella
> <kathleen.capella@arm.com>
> Subject: [PATCH 0/2] Add logic to IAVF to count continuous DD bits for Arm
> 
> This patchset introduces a fix for Arm platforms to the IAVF driver that was
> added to the i40e driver in a previous patchset [1].
> 
> The driver determines which descriptors in the HW ring reference packets
> that are ready to be received by counting those descriptors whose DD bit is
> set to 1. On Arm, the reading of descriptors can be reordered. The CPU may
> be reading descriptors as the NIC is updating them. Tt is possbile that the DD
> bit for a descriptor earlier in the queue is read as not set while the DD bit for
> a descriptor later in the queue is read as set. This patchset ensures only
> contiguous DD bits set to 1 are counted.
> 
> The first patch in this series adds this logic to the bulk Rx path.
> The second patch adds this same logic to the function which reads flexible Rx
> descriptors.
> 
> No performance drop was observed when running l3fwd on N1SDP with a
> single core.
> 
> [1]
> https://patches.dpdk.org/project/dpdk/patch/20210706065404.25137-2-
> joyce.kong@arm.com/
> 
> Kathleen Capella (2):
>   net/iavf: count continuous DD bits for Arm
>   net/iavf: count continuous DD bits for Arm in flex Rx
> 
>  drivers/net/iavf/iavf_rxtx.c | 52 ++++++++++++++++++++++++++++++------
>  1 file changed, 44 insertions(+), 8 deletions(-)
> 
> --
> 2.17.1

Reviewed-by: Qi Zhang <qi.z.zhang@intel.com>

Applied to dpdk-next-net-intel.

Thanks
Qi