On 2019-09-18 10:58, Marcelo Ricardo Leitner wrote:
On Wed, Sep 18, 2019 at 12:17:08PM -0400, Willem de Bruijn wrote:
On Wed, Sep 18, 2019 at 3:25 AM Steffen Klassert
<steffen.klass...@secunet.com> wrote:
>
> This patchset adds support to do GRO/GSO by chaining packets
> of the same flow at the SKB frag_list pointer. This avoids
> the overhead to merge payloads into one big packet, and
> on the other end, if GSO is needed it avoids the overhead
> of splitting the big packet back to the native form.
>
> Patch 1 Enables UDP GRO by default.
>
> Patch 2 adds a netdev feature flag to enable listifyed GRO,
> this implements one of the configuration options discussed
> at netconf 2019.
>
> Patch 3 adds a netdev software feature set that defaults to off
> and assigns the new listifyed GRO feature flag to it.
>
> Patch 4 adds the core infrastructure to do fraglist GRO/GSO.
>
> Patch 5 enables UDP to use fraglist GRO/GSO if configured and no
> GRO supported socket is found.
Very nice feature, Steffen. Aside from questions around performance,
my only question is really how this relates to GSO_BY_FRAGS.
They do the exact same thing AFAICT: they GSO according to a
pre-formatted list of fragments/packets, and not to a specific size
(such as MSS).
More specifically, whether we can remove that in favor of using your
new skb_segment_list. That would actually be a big first step in
simplifying skb_segment back to something manageable.
The main issue (that I know) on obsoleting GSO_BY_FRAGS is that
dealing with frags instead of frag_list was considered easier to be
offloaded, if ever attempted. So this would be a step back on that
aspect. Other than this, it should be doable.
Is there an existing userspace interface for GSO_BY_FRAGS for UDP?
Per my understanding, the current UDP_GSO CMSG option only allows
for a specific GSO_SIZE segmentation.
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
