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Date: Mon, 16 Mar 2026 20:04:34 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Haiyang Zhang <haiyangz@linux.microsoft.com>
Cc: linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, Andrew Lunn
 <andrew@lunn.ch>, "David S. Miller" <davem@davemloft.net>, Eric Dumazet
 <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Simon Horman
 <horms@kernel.org>, Donald Hunter <donald.hunter@gmail.com>, Jonathan
 Corbet <corbet@lwn.net>, Shuah Khan <skhan@linuxfoundation.org>, "Kory
 Maincent (Dent Project)" <kory.maincent@bootlin.com>, Gal Pressman
 <gal@nvidia.com>, Oleksij Rempel <o.rempel@pengutronix.de>, Vadim Fedorenko
 <vadim.fedorenko@linux.dev>, linux-kernel@vger.kernel.org,
 linux-doc@vger.kernel.org, haiyangz@microsoft.com, paulros@microsoft.com
Subject: Re: [PATCH net-next v5 1/3] net: ethtool: add ethtool
 COALESCE_RX_CQE_FRAMES/NSECS
Message-ID: <20260316200434.3a0b99ec@kernel.org>
In-Reply-To: <20260312193725.994833-2-haiyangz@linux.microsoft.com>
References: <20260312193725.994833-1-haiyangz@linux.microsoft.com>
	<20260312193725.994833-2-haiyangz@linux.microsoft.com>
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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.