On Fri, Sep 23, 2011 at 3:25 PM, Ben Pfaff <[email protected]> wrote:
> On Fri, Sep 23, 2011 at 03:24:47PM -0700, Jesse Gross wrote:
>> On Fri, Sep 23, 2011 at 2:53 PM, Ben Pfaff <[email protected]> wrote:
>> > On Fri, Sep 23, 2011 at 02:20:17PM -0700, Jesse Gross wrote:
>> >> Currently it is possible for a client on a single port to generate
>> >> a huge number of packets that miss in the kernel flow table and
>> >> monopolize the userspace/kernel communication path. ??This
>> >> effectively DoS's the machine because no new flow setups can take
>> >> place. ??This adds some additional fairness by separating each upcall
>> >> type for each object in the datapath onto a separate socket, each
>> >> with its own queue. ??Userspace then reads round-robin from each
>> >> socket so other flow setups can still succeed.
>> >>
>> >> Since the number of objects can potentially be large, we don't always
>> >> have a unique socket for each. ??Instead, we create 16 sockets and
>> >> spread the load around them in a round robin fashion. ??It's theoretically
>> >> possible to do better than this with some kind of active load balancing
>> >> scheme but this seems like a good place to start.
>> >>
>> >> Feature #6485
>> >
>> > Seems reasonable.
>> >
>> > Again I'd rate-limit the new warnings in set_upcall_pids().
>>
>> These warnings are actually the same ones as patch 2, just moved.
>> There are some new debug messages but they only trigger when a port is
>> added or the listen mask changes, so it should be pretty low volume.
>>
>> > The call to dpif_flow_dump_next() should supply NULL for the actions
>> > and n_actions parameters since it doesn't need the actions. ??This is a
>> > significant optimization because of how dfpi_linux_flow_dump_next() is
>> > implemented. ??(I think I should have mentioned the same thing in an
>> > earlier patch but I didn't notice until now.)
>>
>> That's a good point, I forgot that it could be NULL.  I also killed
>> off stats and folded this into patch 2.
>
> That all makes sense.  Thank you.

Thanks for reviewing.  I pushed this series.
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