[ovs-dev] [ovs-dev v3] dpif-netdev: Allow to set max capacity of flow on netdev.

[Tonghao Zhang]

On Thu, Jan 9, 2020 at 11:14 PM Ilya Maximets <i.maximets at ovn.org> wrote:
>
> On 09.01.2020 08:36, xiangxia.m.yue at gmail.com wrote:
> > From: Tonghao Zhang <xiangxia.m.yue at gmail.com>
> >
> > For installing more than MAX_FLOWS (65536) flows to netdev datapath.
> > Add the ovs-appctl subcommand "dpif-netdev/pmd-set-max-flow" which
> > can change the flow number which netdev datapath support.
> >
> > Signed-off-by: Tonghao Zhang <xiangxia.m.yue at gmail.com>
>
> Hi.
>
> I'm wondering why we need the flow limit on the datapath level at all?
>
> MAX_FLOWS constant was there from the introduction of dpif-netdev,
> however, later new flow-limit mechanism was implemented that
> controls number of datapath flows in a dynamic way on ofproto level.
>
> So, maybe we can just remove the limit and fully rely on ofproto
> to decide what flow limit we need?  There are no limitations for
> flow table size in dpif-netdev beside the artificial one.
> 'other_config:flow-limit' seems suitable to control this.
Hi all, that is good idea. But the reason that I change MAX_FLOWS to a
var is that
we install the rule via "ovs-appctl dpctl/add-flow" in our product environment,
and there may be too many rules(software limit for hardware flow limit).
ofproto layer is complicated for some developers.
Using the "ovs-appctl dpctl/add-flow" may be easy to control the flows
as I know.
And we do some work on dpctl, for example, revalidator thread does not
delete the flow
we installed via ovs-appctl.

> Ben, what do you think?
>
> Best regards, Ilya Maximets.