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References: <20230219131006.92681-1-nbd@nbd.name> <a66335ec-0911-1902-7585-827b918fe957@nbd.name>
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From:   Eric Dumazet <edumazet@google.com>
Date:   Sun, 19 Feb 2023 22:00:26 +0100
Message-ID: <CANn89iLj1e5fkrPdmaBdhXXaidB6Gvmz_pUjkPiYdqMwv66tFA@mail.gmail.com>
Subject: Re: [RFC v3] net/core: add optional threading for backlog processing
To:     Felix Fietkau <nbd@nbd.name>
Cc:     netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org
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On Sun, Feb 19, 2023 at 4:08 PM Felix Fietkau <nbd@nbd.name> wrote:
>
> On 19.02.23 14:10, Felix Fietkau wrote:
> > When dealing with few flows or an imbalance on CPU utilization, static RPS
> > CPU assignment can be too inflexible. Add support for enabling threaded NAPI
> > for backlog processing in order to allow the scheduler to better balance
> > processing. This helps better spread the load across idle CPUs.
> >
> > Signed-off-by: Felix Fietkau <nbd@nbd.name>


> Sorry, the patch was missing these lines:

Also make sure the following loop won't leak kthreads.

while :
do
 echo 1 >/proc/sys/net/core/backlog_threaded
 echo 0 >/proc/sys/net/core/backlog_threaded
done

Some documentation would also be welcomed (
Documentation/admin-guide/sysctl/net.rst &
Documentation/networking/scaling.rst )