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From: Yannick Vignon <yannick.vignon@oss.nxp.com>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Antoine Tenart <atenart@kernel.org>, Wei Wang <weiwan@google.com>,
	Taehee Yoo <ap420073@gmail.com>,
	Alexander Lobakin <alobakin@pm.me>,
	netdev <netdev@vger.kernel.org>,
	Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Joakim Zhang <qiangqing.zhang@nxp.com>,
	sebastien.laveze@oss.nxp.com,
	Yannick Vignon <yannick.vignon@nxp.com>
Subject: Re: [RFC PATCH net-next v1 1/2] net: add name field to napi struct
Date: Tue, 11 May 2021 18:44:26 +0200	[thread overview]
Message-ID: <2ce5ff9d-7453-f48e-7e84-539752f72be5@oss.nxp.com> (raw)
In-Reply-To: <CANn89i+kZnGHmiVoQSj4Xww7uNwhaj8+XV2C+4a_6k+T4UcY7g@mail.gmail.com>

On 5/6/2021 7:35 PM, Eric Dumazet wrote:
> On Thu, May 6, 2021 at 7:20 PM Yannick Vignon
> <yannick.vignon@oss.nxp.com> wrote:
>>
>> From: Yannick Vignon <yannick.vignon@nxp.com>
>>
>> An interesting possibility offered by the new thread NAPI code is to
>> fine-tune the affinities and priorities of different NAPI instances. In a
>> real-time networking context, this makes it possible to ensure packets
>> received in a high-priority queue are always processed, and with low
>> latency.
>>
>> However, the way the NAPI threads are named does not really expose which
>> one is responsible for a given queue. Assigning a more explicit name to
>> NAPI instances can make that determination much easier.
>>
>> Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
>> -
> 
> Having to change drivers seems a lot of work
> 
> How about exposing thread id (and napi_id eventually) in
> /sys/class/net/eth0/queues/*/kthread_pid  ?
> 

This seemed like a good idea, but after looking into how to actually 
implement it, I can't find a way to "map" rx queues to napi instances. 
Am I missing something?

In the end, I'm afraid that the NAPI<->RX queue mapping is only known 
within the drivers, so we'll have no choice but to modify them
to extract that information somehow.

  reply	other threads:[~2021-05-11 16:44 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06 17:20 [RFC PATCH net-next v1 0/2] Threaded NAPI configurability Yannick Vignon
2021-05-06 17:20 ` [RFC PATCH net-next v1 1/2] net: add name field to napi struct Yannick Vignon
2021-05-06 17:35   ` Eric Dumazet
2021-05-11 16:44     ` Yannick Vignon [this message]
2021-05-06 17:20 ` [RFC PATCH net-next v1 2/2] net: stmmac: use specific name for each NAPI instance Yannick Vignon
2021-05-06 22:18 ` [RFC PATCH net-next v1 0/2] Threaded NAPI configurability Jakub Kicinski
2021-05-11 16:46   ` Yannick Vignon
2021-05-12  1:07     ` Jakub Kicinski

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