From: "Morten Brørup" <mb@smartsharesystems.com>
To: "taozj888" <taozj888@163.com>,
"Stephen Hemminger" <stephen@networkplumber.org>,
<konstantin.v.ananyev@yandex.ru>
Cc: <dev@dpdk.org>
Subject: RE: Re: [PATCH v3 1/2] examples/l3fwd: relax RSS requirement with option
Date: Mon, 13 Nov 2023 13:40:12 +0100 [thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35E9F01A@smartserver.smartshare.dk> (raw)
In-Reply-To: <2645794b.6331.18bc881a674.Coremail.taozj888@163.com>
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From: taozj888 [mailto:taozj888@163.com]
Sent: Monday, 13 November 2023 12.47
At 2023-11-13 07:33:49, "Stephen Hemminger" <stephen@networkplumber.org> wrote:
>On Sun, 12 Nov 2023 07:16:10 +0000
>Trevor Tao <taozj888@163.com> wrote:
>
>> Now the port Rx mq_mode had been set to RTE_ETH_MQ_RX_RSS
>> by default, but some hw and/or virtual interface does not
>> support the RSS and offload mode presupposed, e.g., some
>> virtio interfaces in the cloud don't support
>> RSS and the error msg may like:
>>
>> virtio_dev_configure(): RSS support requested but not supported by
>> the device
>> Port0 dev_configure = -95
>>
>> So to enable the l3fwd running in that environment, the Rx mode requirement
>> can be relaxed to reflect the hardware feature reality here, and the l3fwd
>> can run smoothly then.
>>
>> An option named "relax-rx-mode" is added to enable the relax action
>> here, and it's disabled by default.
>>
>> Signed-off-by: Trevor Tao <taozj888@163.com>
>
>Doesn't need to be an option. The application can just look at the offload
>flags and quickly determine that if multiple queues are being used than
>RSS is required. If device doesn't support RSS, then fallback to single
>queue with a warning.
Hi Stephen:
I think the option here was suggested/required by Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>.
The discussion thread is listed below:
">>>>Should we probably instead have a new commnad-line option to explicitly
>>>>disable RSS?
>>>
>>>>Something like: '--no-rss' or so?
>>> Trevor: the RSS capability for a certain port was got by the rte_eth_dev_info_get() automatically, and we think the user should not care about its status beforehand, but if it's missing, a warning notification for the degrade here would be proposed to make it run smoothly.
>>
>>Personally, I still think it would be better the user will
>>have an ability to disable it explicitly.
>>Same as l3fwd does now with 'parse-ptype'.
>>
"
[Morten]: The "relax-rx-mode" does not explicitly disable RSS, it enables the behavior Stephen suggested: If RSS is not supported by the device, fallback to single queue with a warning. We don't need an option for this; it should be the default behavior.
[Morten]: I think Konstantin was asking for an option "no-rss" (or "disable-rss") to force use of single queue (disable RSS), regardless if the device supports RSS or not.
Thanks,
Trevor Tao
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next prev parent reply other threads:[~2023-11-13 12:40 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-12 7:16 [PATCH v3 0/2] example/l3fwd: relax l3fwd rx RSS/Offload if needed Trevor Tao
2023-11-12 7:16 ` [PATCH v3 1/2] examples/l3fwd: relax RSS requirement with option Trevor Tao
2023-11-12 23:33 ` Stephen Hemminger
2023-11-13 11:47 ` taozj888
2023-11-13 12:40 ` Morten Brørup [this message]
2023-11-13 13:19 ` Konstantin Ananyev
2023-11-13 16:06 ` taozj888
2023-11-12 7:16 ` [PATCH v3 2/2] examples/l3fwd: relax the Offload requirement Trevor Tao
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