Subject: Re: [PATCH net-next v5 1/3] net: ethtool: add ethtool COALESCE_RX_CQE_FRAMES/NSECS

From: Jakub Kicinski <[email-masked]>
Date: Mon, 16 Mar 2026 20:04:34 -0700

On Thu, 12 Mar 2026 12:37:04 -0700 Haiyang Zhang wrote:
> +Rx CQE coalescing allows multiple received packets to be coalesced into a single
> +Completion Queue Entry (CQE). ``ETHTOOL_A_COALESCE_RX_CQE_FRAMES`` describes the
> +maximum number of frames that can be coalesced into a CQE.
> +``ETHTOOL_A_COALESCE_RX_CQE_NSECS`` describes max time in nanoseconds after the
> +first packet arrival in a coalesced CQE to be sent.

Looks good overall, can we broaden the language a bit?
Replace "a single Completion Queue Entry (CQE)" with "a single
Completion Queue Entry (CQE) or descriptor write back"?
I'm assuming your devices don't coalesce CQE writes.
For non-RDMA devices the notion of CQE is a bit foreign but 
descriptor write back coalescing serves similar purpose.
In either case host can't see the frame even if it's busy
polling.

So:

Rx CQE coalescing allows multiple received packets to be coalesced 
into a single Completion Queue Entry (CQE) or descriptor writeback.
``ETHTOOL_A_COALESCE_RX_CQE_FRAMES`` describes the maximum number of 
frames that can be coalesced into a CQE or writeback.
``ETHTOOL_A_COALESCE_RX_CQE_NSECS`` describes max time in nanoseconds 
after the first packet arrival in a coalesced CQE to be sent.