On Tue, Aug 29, 2017 at 07:11:42AM +0000, Darrell Ball wrote:
>
> On 8/22/17, 11:24 PM, "Yuanhan Liu" <[email protected]> wrote:
>
> Hi,
>
> Here is a joint work from Mellanox and Napatech, to enable the flow hw
> offload with the DPDK generic flow interface (rte_flow).
>
> The basic idea is to associate the flow with a mark id (a unit32_t
> number).
> Later, we then get the flow directly from the mark id, bypassing the
> heavy
> emc processing, including miniflow_extract.
>
> The association is done with CMAP in patch 1. It also resues the flow
> APIs introduced while adding the tc offloads. The emc bypassing is
> done
> in patch 2. The flow offload is done in patch 4, which mainly does two
> things:
>
> - translate the ovs match to DPDK rte flow patterns
> - bind those patterns with a MARK action.
>
> Afterwards, the NIC will set the mark id in every pkt's mbuf when it
> matches the flow. That's basically how we could get the flow directly
> from the received mbuf.
>
> While testing with PHY-PHY forwarding with one core and one queue, I
> got
> almost 80% performance boost. For PHY-vhost forwarding, I got about
> 50%
> performance boost.
>
>
> Though that being said, this patchset still has issues unresolved. The
> major issue is that maybe most NIC (for instance, Mellanox and Intel)
> can not support a pure MARK action. It has to be used together with a
> QUEUE action, which in turn needs a queue index. That comes to the
> issue:
> the queue index is not given in the flow context. To make it work,
> patch
> 5 just set the queue index to 0, which is obviously wrong. One
> possible
> solution is to record the rxq and pass it down to the flow creation
> stage. It would be much better, but it's still far away from being
> perfect.
> Because it might have changed the steering rules stealthily, which may
> break the default RSS setup by OVS-DPDK.
>
> If this cannot be solved by removing this restriction, I guess another
> alternative is to actively
> manage flow-queue associations.
do you mean let user provide the set_queue action?
>
> The reason I still want to send it out is to get more
> comments/thoughts
> from community on this whole patchset. Meanwhile, I will try to
> resolve
> the QUEUE action issue.
>
> Note that it's disabled by default, which can be enabled by:
>
> $ ovs-vsctl set Open_vSwitch . other_config:hw-offload=true
>
> Maybe per in-port configuration would alleviate the issue to a certain degree.
Yes, it could be done. I choose it for following reasons:
- the option is already there, used by tc offloads.
- it also simplifies the (first) patchset a bit, IMO.
However, I'm okay with making it per port. What's your suggestion for
this? Making "hw-offload" be port, or introducing another one? If so,
what's your suggestion on the naming?
Thanks for the review. BTW, would you please add me in 'to' or 'cc'
list while replying to me? Otherwise, it's easy to get missed: too
many emails :/
--yliu
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