On Wed, 02 Mar 2022 15:46:37 +0100
Thomas Monjalon <tho...@monjalon.net> wrote:
> 02/03/2022 15:07, Ori Kam:
> > From: lihuisong (C) <lihuis...@huawei.com>
> > > 在 2022/3/1 0:42, Ferruh Yigit 写道:
> > > > On 2/28/2022 3:21 AM, Min Hu (Connor) wrote:
> > > >> From: Huisong Li <lihuis...@huawei.com>
> > > >>
> > > >> RSS will not be enabled if the RTE_ETH_MQ_RX_RSS_FLAG isn't be set in
> > > >> dev_configure phase. However, if this flag isn't set, RSS can be
> > > >> enabled
> > > >> through the ethdev ops and rte_flow API. This behavior is contrary to
> > > >> each
> > > >> other.
> > > >>
> > > >> Fixes: c37ca66f2b27 ("net/hns3: support RSS")
> > > >> Cc: sta...@dpdk.org
> > > >>
> > > >> Signed-off-by: Huisong Li <lihuis...@huawei.com>
> > > >
> > > >
> > > > Hi Huisong, Connor,
> > > >
> > > > Let's get a little more feedback for this patch, cc'ed more people.
> > > >
> > > >
> > > > To enable RSS, multi queue mode should be set to
> > > > 'RTE_ETH_MQ_RX_RSS_FLAG'.
> > > >
> > > > But I wonder if it is required to configure RSS via flow API,
> > >
> > > I do not know the original purpose of adding the RSS configuration in
> > > flow API.
> > >
> > The purpose is simple, this allow to create RSS per rule and not a global
> > one.
> > For example create RSS that sends TCP to some queues while othe RSS will
> > send
> > UDP traffic to different queues.
> >
> > > However, as far as I know, the hash algorithm can be configured via this
> > > API,
> > >
> > > but not via ethdev ops API.
> > >
> > > > and if other PMDs check this configuration for flow API?
> > >
> > > Some PMDs already have similar check in RSS releated ops or rte_flow API.
> > >
> > > For example, hinic, axbge, bnxt, cnxk, otx2, and ena.
>
> I suggest removing these checks.
>
> > From my view point those are two different settings.
> > The RTE_ETH_MQ_RX_RSS_FLAG is global per port while
> > rte_flow is per rule.
> >
> > I think, that if a PMD needs this flag, in order to enable it also for
> > rte_flow then
> > it should be documented in the release note of the PMD.
> > It is a valid use case that the default traffic will not have RSS and only
> > rules created by
> > rte_flow will have the RSS, for matching traffc.
>
> I think RTE_ETH_MQ_RX_RSS_FLAG should not be required by any PMD
> for rte_flow RSS rules.
>
>
Agreed.
The ideal state around RSS would be:
- global settings affect the default started queues when device is started.
if RSS is enabled and 4 queues are started, then RSS would happen for
received
packets across those 4 queues.
- when adding new flow related rx:
- new queues could be started - BUT not part of original RSS
- new rte_flow rule can do RSS against the new flow:
example:
start queues 4,5,6,7
rte_flow match TCP port 80 and process on queues 4,5,6,7 with RSS
This is a mess today, most devices work differently and there is no reference
software
implementation. In an ideal state, there would be a reference software
implementation
that implements all of rte_flow, and all new hardware support would have to
work the same
as the reference implementation. And there would be a full CI test suite around
rte_flow.
