From: David Miller <davem@davemloft.net>
To: brouer@redhat.com
Cc: netdev@vger.kernel.org, ilias.apalodimas@linaro.org,
lorenzo@kernel.org, dsahern@gmail.com, toke@toke.dk,
saeedm@mellanox.com, tariqt@mellanox.com, kuba@kernel.org,
andrew@lunn.ch, thomas.petazzoni@bootlin.com
Subject: Re: [net-next PATCH] mvneta: add XDP ethtool errors stats for TX to driver
Date: Mon, 02 Mar 2020 11:29:58 -0800 (PST) [thread overview]
Message-ID: <20200302.112958.1038288292834637833.davem@davemloft.net> (raw)
In-Reply-To: <158315678810.1983667.11239367181663328821.stgit@firesoul>
From: Jesper Dangaard Brouer <brouer@redhat.com>
Date: Mon, 02 Mar 2020 14:46:28 +0100
> Adding ethtool stats for when XDP transmitted packets overrun the TX
> queue. This is recorded separately for XDP_TX and ndo_xdp_xmit. This
> is an important aid for troubleshooting XDP based setups.
>
> It is currently a known weakness and property of XDP that there isn't
> any push-back or congestion feedback when transmitting frames via XDP.
> It's easy to realise when redirecting from a higher speed link into a
> slower speed link, or simply two ingress links into a single egress.
> The situation can also happen when Ethernet flow control is active.
>
> For testing the patch and provoking the situation to occur on my
> Espressobin board, I configured the TX-queue to be smaller (434) than
> RX-queue (512) and overload network with large MTU size frames (as a
> larger frame takes longer to transmit).
>
> Hopefully the upcoming XDP TX hook can be extended to provide insight
> into these TX queue overflows, to allow programmable adaptation
> strategies.
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Applied, thanks Jesper.
prev parent reply other threads:[~2020-03-02 19:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 13:46 [net-next PATCH] mvneta: add XDP ethtool errors stats for TX to driver Jesper Dangaard Brouer
2020-03-02 14:13 ` Lorenzo Bianconi
2020-03-02 19:29 ` David Miller [this message]
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