[ovs-dev] [PATCH 2/2] ovs-dpctl: Add mega flow support

Jesse Gross jesse at nicira.com
Thu Jun 20 01:42:59 UTC 2013


I added most of the ones that seemed important during my cleanups
yesterday. The only other thing that comes to mind is a description of
how updates are handled (such as the fact that the new mask is
ignored).

On Wed, Jun 19, 2013 at 3:04 PM, Andy Zhou <azhou at nicira.com> wrote:
> Good idea. There may be other aspects of the mega related kernel ABI needs
> document as well. Wonder if Justin and Jesse have more inputs on this.
>
>
> On Wed, Jun 19, 2013 at 2:55 PM, Ben Pfaff <blp at nicira.com> wrote:
>>
>> OK, can we add that in the tree somewhere, maybe datapath/README?
>>
>> Thanks,
>>
>> Ben.
>>
>> On Wed, Jun 19, 2013 at 02:52:52PM -0700, Andy Zhou wrote:
>> > It is a good idea to capture this information in a table.   The
>> > following
>> > table should be accurate:
>> >
>> > Pre-megaflow:
>> >
>> >     type                mask               matches
>> >     ----------------    ----------------   ---------------------------
>> >     eth_type(0x600+)    <none>       specified Ethertype II, or valid
>> > 802.3
>> > SNAP
>> >                                                    packet with valid
>> > eth_type.
>> >  Ethertype.
>> >     <none>              <none>           any non-Ethernet II frame,
>> > except
>> > valid 802.3 SNAP
>> >                                                    packet with valid
>> > eth_type.
>> >
>> > Post-megaflow:
>> >
>> >     type                mask               matches
>> >     ----------------    ----------------   ---------------------------
>> >     eth_type(0x600+)    eth_type(0xffff)   specified Ethertype II
>> > Ethertype, or valid 802.3 SNAP packet with valid eth_type.
>> >     eth_type(0x600+)    eth_type(0)        any Ethertype II frame or
>> > non-Ethernet II frame.
>> >     <none>              eth_type(0xffff)   any non-Ethernet II frame,
>> > except valid 802.3 SNAP packet with valid eth_type.
>> >
>> > --andy
>> >
>> >
>> >
>> >
>> > On Wed, Jun 19, 2013 at 1:42 PM, Ben Pfaff <blp at nicira.com> wrote:
>> >
>> > > I don't really care about the formatting, only about the kernel ABI.
>> > >
>> > > Pre-megaflows, the ABI was:
>> > >
>> > >     type                mask               matches
>> > >     ----------------    ----------------   ---------------------------
>> > >     eth_type(0x600+)    <none>             specified Ethertype II
>> > > Ethertype.
>> > >     <none>              <none>             any non-Ethernet II frame
>> > >
>> > > Now, my understanding is that the above continue to be valid, with the
>> > > same meanings, but the following are also supported:
>> > >
>> > >     type                mask               matches
>> > >     ----------------    ----------------   ---------------------------
>> > >     eth_type(0x600+)    eth_type(0xffff)   specified Ethertype II
>> > > Ethertype.
>> > >     eth_type(0x600+)    eth_type(0)        any Ethertype II frame
>> > >     <none>              eth_type(0xffff)   any non-Ethernet II frame
>> > >
>> > > Is that right?
>> > >
>> > > On Wed, Jun 19, 2013 at 10:40:28AM -0700, Andy Zhou wrote:
>> > > > We will continue to allow missing eth_type in the netlink attribute
>> > > > to
>> > > > imply Ethernet II type. 802.3 frames requires a specific eth_type
>> > > > attribute.
>> > >
>> > > I don't understand the first sentence.  We have never interpreted a
>> > > missing eth_type as implying an Ethernet II frame; the opposite, in
>> > > fact: a missing eth_type matches only non-Ethernet II frames.
>> > >
>> > > > With Mega flows, we further require a missing eth_type in the key
>> > > attribute
>> > > > to have a exact match (oxffff) in the eth_type of the mask attribute
>> > > > (if
>> > > > present).
>> > >
>> > > That's really weird.  What's the rationale?
>> > >
>> > > Thanks,
>> > >
>> > > Ben.
>> > >
>
>
>
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