Re: [Intel-wired-lan] [net-next v3 2/2] igc: Link queues to NAPI instances

["Lifshits, Vitaly" <vitaly.lifshits@intel.com>]

On 10/21/2024 8:48 PM, Vinicius Costa Gomes wrote:
> Joe Damato <jdamato@fastly.com> writes:
> 
>> Link queues to NAPI instances via netdev-genl API so that users can
>> query this information with netlink. Handle a few cases in the driver:
>>    1. Link/unlink the NAPIs when XDP is enabled/disabled
>>    2. Handle IGC_FLAG_QUEUE_PAIRS enabled and disabled
>>
>> Example output when IGC_FLAG_QUEUE_PAIRS is enabled:
>>
>> $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
>>                           --dump queue-get --json='{"ifindex": 2}'
>>
>> [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'},
>>   {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'},
>>   {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'rx'},
>>   {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'rx'},
>>   {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'},
>>   {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'tx'},
>>   {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'},
>>   {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}]
>>
>> Since IGC_FLAG_QUEUE_PAIRS is enabled, you'll note that the same NAPI ID
>> is present for both rx and tx queues at the same index, for example
>> index 0:
>>
>> {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'},
>> {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'},
>>
>> To test IGC_FLAG_QUEUE_PAIRS disabled, a test system was booted using
>> the grub command line option "maxcpus=2" to force
>> igc_set_interrupt_capability to disable IGC_FLAG_QUEUE_PAIRS.
>>
>> Example output when IGC_FLAG_QUEUE_PAIRS is disabled:
>>
>> $ lscpu | grep "On-line CPU"
>> On-line CPU(s) list:      0,2
>>
>> $ ethtool -l enp86s0  | tail -5
>> Current hardware settings:
>> RX:		n/a
>> TX:		n/a
>> Other:		1
>> Combined:	2
>>
>> $ cat /proc/interrupts  | grep enp
>>   144: [...] enp86s0
>>   145: [...] enp86s0-rx-0
>>   146: [...] enp86s0-rx-1
>>   147: [...] enp86s0-tx-0
>>   148: [...] enp86s0-tx-1
>>
>> 1 "other" IRQ, and 2 IRQs for each of RX and Tx, so we expect netlink to
>> report 4 IRQs with unique NAPI IDs:
>>
>> $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
>>                           --dump napi-get --json='{"ifindex": 2}'
>> [{'id': 8196, 'ifindex': 2, 'irq': 148},
>>   {'id': 8195, 'ifindex': 2, 'irq': 147},
>>   {'id': 8194, 'ifindex': 2, 'irq': 146},
>>   {'id': 8193, 'ifindex': 2, 'irq': 145}]
>>
>> Now we examine which queues these NAPIs are associated with, expecting
>> that since IGC_FLAG_QUEUE_PAIRS is disabled each RX and TX queue will
>> have its own NAPI instance:
>>
>> $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
>>                           --dump queue-get --json='{"ifindex": 2}'
>> [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'},
>>   {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'},
>>   {'id': 0, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'},
>>   {'id': 1, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}]
>>
>> Signed-off-by: Joe Damato <jdamato@fastly.com>
> 
> 
> Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> 
Reviewed-by: Vitaly Lifshits <vitaly.lifshits@intel.com>

> 
> Cheers,