From: Denis Kirjanov <kda@linux-powerpc.org>
To: "Jürgen Groß" <jgross@suse.com>
Cc: netdev@vger.kernel.org, ilias.apalodimas@linaro.org,
wei.liu@kernel.org, paul@xen.org
Subject: Re: [PATCH net-next v4] xen networking: add basic XDP support for xen-netfront
Date: Wed, 18 Mar 2020 15:50:19 +0300 [thread overview]
Message-ID: <CAOJe8K3gDJrdKz9zVZNj=N76GygMnPbCKM0-kVfoV53fASAefg@mail.gmail.com> (raw)
In-Reply-To: <f75365c7-a3ca-cf12-b2fc-e48652071795@suse.com>
On 3/18/20, Jürgen Groß <jgross@suse.com> wrote:
> On 16.03.20 14:09, Denis Kirjanov wrote:
>> The patch adds a basic XDP processing to xen-netfront driver.
>>
>> We ran an XDP program for an RX response received from netback
>> driver. Also we request xen-netback to adjust data offset for
>> bpf_xdp_adjust_head() header space for custom headers.
>
> This is in no way a "verbose patch descriprion".
>
> I'm missing:
>
> - Why are you doing this. "Add XDP support" is not enough, for such
> a change I'd like to see some performance numbers to get an idea
> of the improvement to expect, or which additional functionality
> for the user is available.
Ok, I'll try to measure some numbers.
>
> - A short description for me as a Xen maintainer with only basic
> networking know-how, what XDP programs are about (a link to some
> more detailed doc is enough, of course) and how the interface
> is working (especially for switching between XDP mode and normal
> SKB processing).
You can search for the "A practical introduction to XDP" tutorial.
Actually there is a lot of information available regarding XDP, you
can easily find it.
>
> - A proper description of the netfront/netback communication when
> enabling or disabling XDP mode (who is doing what, is silencing
> of the virtual adapter required, ...).
Currently we need only a header offset from netback driver so that we can put
custom encapsulation header if required and that's done using xen bus
state switching,
so that:
- netback tells that it can adjust the header offset
- netfront part reads it
>
> - Reasoning why the suggested changes of frontend and backend state
> are no problem for special cases like hot-remove of an interface or
> live migration or suspend of the guest.
I've put the code to talk_to_netback which is called "when first
setting up, and when resuming"
If you see a problem with that please share.
>
> Finally I'd like to ask you to split up the patch into a netfront and
> a netback one.
Ok, will do.
Thanks!
>
>
> Juergen
>
next prev parent reply other threads:[~2020-03-18 12:50 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-16 13:09 [PATCH net-next v4] xen networking: add basic XDP support for xen-netfront Denis Kirjanov
2020-03-16 15:44 ` Jesper Dangaard Brouer
2020-03-18 12:31 ` Denis Kirjanov
2020-03-16 15:52 ` Jesper Dangaard Brouer
2020-03-18 12:30 ` Denis Kirjanov
2020-03-18 10:27 ` Paul Durrant
2020-03-18 11:16 ` Jürgen Groß
2020-03-18 12:50 ` Denis Kirjanov [this message]
2020-03-18 13:11 ` Jürgen Groß
2020-03-23 10:15 ` Denis Kirjanov
2020-03-23 10:27 ` Jürgen Groß
2020-03-23 10:49 ` Denis Kirjanov
2020-03-23 11:00 ` Jürgen Groß
2020-03-30 12:16 ` Denis Kirjanov
2020-03-30 12:55 ` Jürgen Groß
2020-03-30 13:09 ` Denis Kirjanov
2020-03-30 13:13 ` Jürgen Groß
2020-03-30 13:18 ` Denis Kirjanov
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