On 10/10/19 11:23 AM, David Marchand wrote:
On Thu, Oct 10, 2019 at 10:14 AM Andrew Rybchenko
<arybche...@solarflare.com> wrote:
On 10/10/19 10:42 AM, Thomas Monjalon wrote:
09/10/2019 13:24, Andrew Rybchenko:
On 10/9/19 1:41 PM, Tiwei Bie wrote:
My understanding is that, setting mq_mode to ETH_MQ_RX_NONE means
no method is enforced on how to route packets to MQs.
I'm not sure. It is definitely a place to be improved in
ethdev documentation. Thomas, Ferruh, what do you think?
Is it really a definition of ETH_MQ_RX_NONE?
I think it means everything go to queue 0.
I understand it this way as well.
The comment says no DCB, RSS or VMDQ.
It looks like the "NONE" value has been abused for some custom steering.
We have two options:
- document NONE as a possible case of custom steering
- add a new CUSTOM value
I'd prefer to say that ETH_MQ_RX_RSS with rss_hf equal to 0 means
unspecified/unknown steering. If application just want to spread
traffic across many Rx queues, it is natural choice to say that
it want RSS, but do not care about spreading algorithm etc.
It allows driver use recommended defaults if rss_hf is controllable,
or just spread in virtio case.
RSS is about maintaining affinity of a "flow" (as in packets sharing
the same l3/l4 tuples) to a specific queue.
Here, we can have packets from a same flow on any queue depending on
what happened on the vhost side.
Interesting. I'd like to know a bit more about it. I didn't know that
it is so unstable. Could someone who knows the topic well add
a bit more information about it.
I prefer we describe this behavior as something else than RSS.
