From: Jakub Kicinski <kuba@kernel.org>
To: Wei Fang <wei.fang@nxp.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
"davem@davemloft.net" <davem@davemloft.net>,
"edumazet@google.com" <edumazet@google.com>,
"pabeni@redhat.com" <pabeni@redhat.com>,
"ast@kernel.org" <ast@kernel.org>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
"hawk@kernel.org" <hawk@kernel.org>,
"john.fastabend@gmail.com" <john.fastabend@gmail.com>,
Shenwei Wang <shenwei.wang@nxp.com>,
Clark Wang <xiaoning.wang@nxp.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
dl-linux-imx <linux-imx@nxp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: Re: [PATCH net 3/3] net: fec: increase the size of tx ring and update thresholds of tx ring
Date: Wed, 5 Jul 2023 20:11:55 -0700 [thread overview]
Message-ID: <20230705201155.5a05bf18@kernel.org> (raw)
In-Reply-To: <AM5PR04MB3139ED2B0F74BBD00B85A448882CA@AM5PR04MB3139.eurprd04.prod.outlook.com>
On Thu, 6 Jul 2023 01:44:49 +0000 Wei Fang wrote:
> > But you shouldn't restart the queue for a single packet either.
> > Restarting for a single packet wastes CPU cycles as there will be much more
> > stop / start operations. Two large packets seem like the absolute minimum
> > reasonable wake threshold.
> >
> > Setting tx_stop_threshold to MAX_SKB_FRAGS doesn't seem right either, as
> > you won't be able to accept a full TSO frame.
> >
> Maybe I should keep the tx_stop_threshold unchanged, so that the queue is
> to be stopped if the available BDs is not enough for a full TSO frame to be attached.
> And then just change tx_wake_threshold to tx_stop_threshold + 1, which I think it's
> more reasonable.
How about at least tx_stop_threshold + 2 * MAX_SKB_FRAGS ?
If a queue of hundreds of entries is overflowing, we should be able
to apply a hysteresis of a few tens of entries. Do you see a
difference in drops? The packets from the stack should preferably stay
in the qdiscs instead of the driver queue, where AQM and scheduling can
be applied.
next prev parent reply other threads:[~2023-07-06 3:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-04 8:29 [PATCH net 0/3] net: fec: fix some issues of ndo_xdp_xmit() wei.fang
2023-07-04 8:29 ` [PATCH net 1/3] net: fec: dynamically set the NETDEV_XDP_ACT_NDO_XMIT feature of XDP wei.fang
2023-07-04 23:41 ` Andrew Lunn
2023-07-04 23:54 ` Toke Høiland-Jørgensen
2023-07-05 6:31 ` Wei Fang
2023-07-04 8:29 ` [PATCH net 2/3] net: fec: recycle pages for transmitted XDP frames wei.fang
2023-07-04 23:48 ` Andrew Lunn
2023-07-05 1:56 ` Wei Fang
2023-07-04 8:29 ` [PATCH net 3/3] net: fec: increase the size of tx ring and update thresholds of tx ring wei.fang
2023-07-05 0:25 ` Andrew Lunn
2023-07-05 6:20 ` Wei Fang
2023-07-05 18:11 ` Jakub Kicinski
2023-07-06 1:44 ` Wei Fang
2023-07-06 3:11 ` Jakub Kicinski [this message]
2023-07-06 6:14 ` Wei Fang
2023-07-08 19:03 ` Andrew Lunn
2023-07-10 6:16 ` Wei Fang
2023-07-12 1:16 ` Andrew Lunn
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