Commit aec5514d authored Oct 09, 2024 by Joe Damato Committed by Jakub Kicinski Oct 10, 2024

tg3: Link queues to NAPIs



Link queues to NAPIs using the netdev-genl API so this information is
queryable.

First, test with the default setting on my tg3 NIC at boot with 1 TX
queue:

$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
                         --dump queue-get --json='{"ifindex": 2}'

[{'id': 0, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'},
 {'id': 1, 'ifindex': 2, 'napi-id': 8195, 'type': 'rx'},
 {'id': 2, 'ifindex': 2, 'napi-id': 8196, 'type': 'rx'},
 {'id': 3, 'ifindex': 2, 'napi-id': 8197, 'type': 'rx'},
 {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}]

Now, adjust the number of TX queues to be 4 via ethtool:

$ sudo ethtool -L eth0 tx 4
$ sudo ethtool -l eth0 | tail -5
Current hardware settings:
RX:		4
TX:		4
Other:		n/a
Combined:	n/a

Despite "Combined: n/a" in the ethtool output, /proc/interrupts shows
the tg3 has renamed the IRQs to be combined:

343: [...] eth0-0
344: [...] eth0-txrx-1
345: [...] eth0-txrx-2
346: [...] eth0-txrx-3
347: [...] eth0-txrx-4

Now query this via netlink to ensure the queues are linked properly to
their NAPIs:

$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
                         --dump queue-get --json='{"ifindex": 2}'
[{'id': 0, 'ifindex': 2, 'napi-id': 8960, 'type': 'rx'},
 {'id': 1, 'ifindex': 2, 'napi-id': 8961, 'type': 'rx'},
 {'id': 2, 'ifindex': 2, 'napi-id': 8962, 'type': 'rx'},
 {'id': 3, 'ifindex': 2, 'napi-id': 8963, 'type': 'rx'},
 {'id': 0, 'ifindex': 2, 'napi-id': 8960, 'type': 'tx'},
 {'id': 1, 'ifindex': 2, 'napi-id': 8961, 'type': 'tx'},
 {'id': 2, 'ifindex': 2, 'napi-id': 8962, 'type': 'tx'},
 {'id': 3, 'ifindex': 2, 'napi-id': 8963, 'type': 'tx'}]

As you can see above, id 0 for both TX and RX share a NAPI, NAPI ID
8960, and so on for each queue index up to 3.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20241009175509.31753-3-jdamato@fastly.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 25118cce

drivers/net/ethernet/broadcom/tg3.c

+35 −4

Original line number	Diff line number	Diff line
		@@ -7395,18 +7395,49 @@ static int tg3_poll(struct napi_struct *napi, int budget)

		static void tg3_napi_disable(struct tg3 *tp)
		{
		int txq_idx = tp->txq_cnt - 1;
		int rxq_idx = tp->rxq_cnt - 1;
		struct tg3_napi *tnapi;
		int i;

		for (i = tp->irq_cnt - 1; i >= 0; i--)
		napi_disable(&tp->napi[i].napi);
		for (i = tp->irq_cnt - 1; i >= 0; i--) {
		tnapi = &tp->napi[i];
		if (tnapi->tx_buffers) {
		netif_queue_set_napi(tp->dev, txq_idx,
		NETDEV_QUEUE_TYPE_TX, NULL);
		txq_idx--;
		}
		if (tnapi->rx_rcb) {
		netif_queue_set_napi(tp->dev, rxq_idx,
		NETDEV_QUEUE_TYPE_RX, NULL);
		rxq_idx--;
		}
		napi_disable(&tnapi->napi);
		}
		}

		static void tg3_napi_enable(struct tg3 *tp)
		{
		int txq_idx = 0, rxq_idx = 0;
		struct tg3_napi *tnapi;
		int i;

		for (i = 0; i < tp->irq_cnt; i++)
		napi_enable(&tp->napi[i].napi);
		for (i = 0; i < tp->irq_cnt; i++) {
		tnapi = &tp->napi[i];
		napi_enable(&tnapi->napi);
		if (tnapi->tx_buffers) {
		netif_queue_set_napi(tp->dev, txq_idx,
		NETDEV_QUEUE_TYPE_TX,
		&tnapi->napi);
		txq_idx++;
		}
		if (tnapi->rx_rcb) {
		netif_queue_set_napi(tp->dev, rxq_idx,
		NETDEV_QUEUE_TYPE_RX,
		&tnapi->napi);
		rxq_idx++;
		}
		}
		}

		static void tg3_napi_init(struct tg3 *tp)