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25118cce66
Link IRQs to NAPI instances with netif_napi_set_irq. This information
can be queried with the netdev-genl API.
Begin by testing my tg3 device in its default state: 1 TX queue and 4 RX
queues.
Compare the output of /proc/interrupts for my tg3 device with the output of
netdev-genl after applying this patch:
$ cat /proc/interrupts | grep eth0
343: [...] eth0-tx-0
344: [...] eth0-rx-1
345: [...] eth0-rx-2
346: [...] eth0-rx-3
347: [...] eth0-rx-4
As you can see above, tg3 has named the IRQs such that there is a
dedicated tx IRQ and 4 dedicated rx IRQs, for a total of 5 IRQs.
$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
--dump napi-get --json='{"ifindex": 2}'
[{'id': 8197, 'ifindex': 2, 'irq': 347},
{'id': 8196, 'ifindex': 2, 'irq': 346},
{'id': 8195, 'ifindex': 2, 'irq': 345},
{'id': 8194, 'ifindex': 2, 'irq': 344},
{'id': 8193, 'ifindex': 2, 'irq': 343}]
Netlink displays the same IRQs as above, noting that each is mapped to a
unique NAPI instance.
Now, reconfigure the NIC to have 4 TX queues and 4 RX queues:
$ sudo ethtool -L eth0 rx 4 tx 4
$ sudo ethtool -l eth0 | tail -5
Current hardware settings:
RX: 4
TX: 4
Other: n/a
Combined: n/a
Examine /proc/interrupts once again, noting that tg3 will now rename the
IRQs to suggest that they are combined tx and rx without allocating
additional IRQs, so the total IRQ count in /proc/interrupts is
unchanged:
343: [...] eth0-0
344: [...] eth0-txrx-1
345: [...] eth0-txrx-2
346: [...] eth0-txrx-3
347: [...] eth0-txrx-4
Check the output from netlink again:
$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
--dump napi-get --json='{"ifindex": 2}'
[{'id': 8973, 'ifindex': 2, 'irq': 347},
{'id': 8972, 'ifindex': 2, 'irq': 346},
{'id': 8971, 'ifindex': 2, 'irq': 345},
{'id': 8970, 'ifindex': 2, 'irq': 344},
{'id': 8969, 'ifindex': 2, 'irq': 343}]
Signed-off-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20241009175509.31753-2-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.