netdev - Re: [PATCH bpf-next 05/12] xsk: eliminate the RX batch size

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Message-ID: <CAJ8uoz18h8qrd-w6eakW1k+ZNW=erB7wLqO9+H50iZ4J3cXg5A@mail.gmail.com>
Date:   Mon, 9 Dec 2019 14:07:06 +0100
From:   Magnus Karlsson <magnus.karlsson@...il.com>
To:     Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Cc:     Magnus Karlsson <magnus.karlsson@...el.com>,
        Björn Töpel <bjorn.topel@...el.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Network Development <netdev@...r.kernel.org>,
        Jonathan Lemon <jonathan.lemon@...il.com>,
        bpf <bpf@...r.kernel.org>, Saeed Mahameed <saeedm@...lanox.com>,
        jeffrey.t.kirsher@...el.com,
        "Fijalkowski, Maciej" <maciej.fijalkowski@...el.com>,
        Maciej Fijalkowski <maciejromanfijalkowski@...il.com>
Subject: Re: [PATCH bpf-next 05/12] xsk: eliminate the RX batch size

On Mon, Dec 9, 2019 at 11:17 AM Sergei Shtylyov
<sergei.shtylyov@...entembedded.com> wrote:
>
> Hello!
>
> On 09.12.2019 10:56, Magnus Karlsson wrote:
>
> > In the xsk consumer ring code there is a variable call RX_BATCH_SIZE
>
>     Called?

Yes, definitely. Will fix.

Thanks: Magnus

> > that dictates the minimum number of entries that we try to grab from
> > the fill and Tx rings. In fact, the code always try to grab the
>    ^^^^^^^^^^^^^^^^^^^^^ hm, are you sure there's no typo here?
>
> > maximum amount of entries from these rings. The only thing this
> > variable does is to throw an error if there is less than 16 (as it is
> > defined) entries on the ring. There is no reason to do this and it
> > will just lead to weird behavior from user space's point of view. So
> > eliminate this variable.
> >
> > With this change, we will be able to simplify the xskq_nb_free and
> > xskq_nb_avail code in the next commit.
> >
> > Signed-off-by: Magnus Karlsson <magnus.karlsson@...el.com>
> [...]
>
> MBR, Sergei
>