[ovs-dev] [PATCH] dpif-netdev: Add miniflow bits to dump-flows.

Stokes, Ian ian.stokes at intel.com
Wed Oct 21 15:47:26 UTC 2020

> On 6/8/20 5:36 PM, William Tu wrote:
> > On Mon, Jun 8, 2020 at 7:01 AM Ilya Maximets <i.maximets at ovn.org> wrote:
> >>
> >> On 5/14/20 4:11 PM, William Tu wrote:
> >>> The 'dpctl/dump-flows -m' only shows the number of 1-bit in the
> >>> miniflow map, the patch outputs additional miniflow bits after it.
> >>> The format will be
> >>>   dp-extra-info:miniflow_bits(count_1bit(unit0):unit0,
> >>>                               count_1bit(unit1):unit1)
> >>> Example:
> >>>   dp-extra-info:miniflow_bits(4:0x30c0000000000000,1:0x400)
> >>>
> >>> By searching the unique miniflow bits, we know the number of subtables,
> >>> and for earch subtables, the fields it matches on.
> >>
> >> Hi.
> >>
> >> Beside the curiosity what is the purpose of printing this information?
> >> How can it be used?
> >>
> > So from the bitmap we can know which field in the 'struct flow' this
> > subtable is matching on. And collecting all the bitmaps from dpctl/dump-flow,
> > we can know which fields are used to match more frequently than others.
> Don't you have all this information from the flow match?

Hi William,

I haven't seen feedback to Ilyas point above. I guess from our side I was think the same as Ilya, if this is available already then do we need to duplicate here?

It may make sense if OVS doesn't have a way to easily map the bits back to its "struct flow" name

That being said I suppose it's a question of usability, could the above example be improved further for usability, so something like:

Example: dp-extra-info:miniflow_bits(4: ether src, ether dst,ipv4,udp  1: udp)


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