Re: [PATCH net-next v1 2/3] net: dsa: ar9331: add support for pause stats

From: Andrew Lunn <andrew@lunn.ch>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Vladimir Oltean <olteanv@gmail.com>,
	Oleksij Rempel <o.rempel@pengutronix.de>,
	Woojung Huh <woojung.huh@microchip.com>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>,
	kernel@pengutronix.de, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, Lukas Wunner <lukas@wunner.de>,
	UNGLinuxDriver@microchip.com
Subject: Re: [PATCH net-next v1 2/3] net: dsa: ar9331: add support for pause stats
Date: Tue, 28 Jun 2022 09:22:53 +0200	[thread overview]
Message-ID: <YrqsTY0uUy4AwKHN@lunn.ch> (raw)
In-Reply-To: <20220627200959.683de11b@kernel.org>

> Yeah, the corrections are always iffy. I understand the doubts, and we
> can probably leave things "under-specified" until someone with a strong
> preference comes along. But I hope that the virt example makes it clear
> that neither of the choices is better (SR-IOV NICs would have to start
> adding the pause if we declare rtnl stats as inclusive).
> 
> I can see advantages to both counting (they are packets) and not
> counting those frames (Linux doesn't see them, they get "invented" 
> by HW).
> 
> Stats are hard.

I doubt we can define it either way. I once submitted a patch for one
driver to make it ignore CRC bytes. It then gave the exact same counts
as another hardware i was using, making the testing i was doing
simpler.

The patch got rejected simply because we have both, with CRC and
without CRC, neither is correct, neither is wrong.

So i would keep it KISS, pause frames can be included, but i would not
go to extra effort to include them, or to exclude them.

   Andrew