Re: [PATCH] net/ixgbevf: fix RSS init for x550 nics

Re: [PATCH] net/ixgbevf: fix RSS init for x550 nics

[Bruce Richardson]

On Tue, Feb 27, 2024 at 05:26:06PM +0000, Medvedkin, Vladimir wrote:
> 
> On 15/02/2024 13:31, edwin.brossette@6wind.com wrote:
> > From: Edwin Brossette <edwin.brossette@6wind.com>
> > 
> > Different Intel nics with the igxbe pmd do not handle RSS in the same
> > way when working with virtualization. While some nics like Intel 82599ES
> > only have a single RSS table in the device and leave all rss features to
> > be handled by the pf, some other nics like x550 let the vf handle RSS
> > features. This can lead to different behavior when rss is enabled
> > depending on the model of nic used.
> > 
> > In particular, it occurred that ixgbevf_dev_rx_init() do not initiate
> > rss parameters at device init, even if the multi-queue mode option is
> > set in the device configuration (ie: RTE_ETH_MQ_RX_RSS is set). Note
> > that this issue went unnoticed until now, probably because some nics do
> > not really have support for RSS in virtualization mode.
> > 
> > Thus, depending on the nic used, we can we find ourselves in a situation
> > where RSS is not configured despite being enabled. This will cause
> > serious performance issues because the RSS reta will be fully zeroed,
> > causing all packets to go only in the first queue and leaving all the
> > others empty.
> > 
> > By looking at ixgbe_reta_size_get(), we can see that only X550 nic
> > models have a non zero reta size set in vf mode. Thus add a call to
> > ixgbe_rss_configure() for these cards in ixgbevf_dev_rx_init() if the
> > option to enable RSS is set.
> > 
> > Fixes: f4d1598ee14f ("ixgbevf: support RSS config on x550")

+ Cc: stable@dpdk.org

> > Signed-off-by: Edwin Brossette <edwin.brossette@6wind.com>
> > ---
> Acked-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
> 

Applied to next-net-intel tree.
Thanks,
/Bruce