Re: [dpdk-dev] [PATCH v2 3/4] net/ixgbe: convert to new Rx offloads API

["Dai, Wei" <wei.dai@intel.com>]

Hi, Konstantin
Thanks for your feedback.

> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Thursday, March 15, 2018 5:48 AM
> To: Dai, Wei <wei.dai@intel.com>; Lu, Wenzhuo <wenzhuo.lu@intel.com>
> Cc: dev@dpdk.org
> Subject: RE: [PATCH v2 3/4] net/ixgbe: convert to new Rx offloads API
> 
> Hi Wei,
> 
> > -----Original Message-----
> > From: Dai, Wei
> > Sent: Wednesday, March 7, 2018 1:06 PM
> > To: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Ananyev, Konstantin
> > <konstantin.ananyev@intel.com>
> > Cc: dev@dpdk.org; Dai, Wei <wei.dai@intel.com>
> > Subject: [PATCH v2 3/4] net/ixgbe: convert to new Rx offloads API
> >
> > Ethdev Rx offloads API has changed since:
> > commit ce17eddefc20 ("ethdev: introduce Rx queue offloads API") This
> > commit support the new Rx offloads API.
> >
> > Signed-off-by: Wei Dai <wei.dai@intel.com>
> > ---
> >  drivers/net/ixgbe/ixgbe_ethdev.c          |  93 +++++++++--------
> >  drivers/net/ixgbe/ixgbe_ipsec.c           |   8 +-
> >  drivers/net/ixgbe/ixgbe_rxtx.c            | 163
> ++++++++++++++++++++++++++----
> >  drivers/net/ixgbe/ixgbe_rxtx.h            |   3 +
> >  drivers/net/ixgbe/ixgbe_rxtx_vec_common.h |   2 +-
> >  drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c   |   2 +-
> >  6 files changed, 205 insertions(+), 66 deletions(-)
> >
> > +uint64_t
> > +ixgbe_get_rx_queue_offloads(struct rte_eth_dev *dev) {
> > +	uint64_t offloads;
> > +	struct ixgbe_hw *hw =
> > +IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> > +
> > +	offloads = DEV_RX_OFFLOAD_HEADER_SPLIT;
> 
> As I can see I ixgbe all header_split code is enabled only if
> RTE_HEADER_SPLIT_ENABLE is on.
> It is off by default and I doubt anyone really using it these days.
> So I think the best thing would be not to advertise
> DEV_RX_OFFLOAD_HEADER_SPLIT for ixgbe at all, and probably remove
> related code.
> If you'd prefer to keep it, then at least we should set that capability only at
> #ifdef RTE_HEADER_SPLIT_ENABLE.
> Another thing - 	it should be per port, not per queue.
> Thought I think better is just to remove it completely.
I will set this header splitting capability in #ifdef RTE_HEADER_SPLIT_ENABLE in my next patch set.
I think it is a per queue capability as it can be configured on the register IXGBE_SRRCTL of every Rx queue
In this code line: IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(rxq->reg_idx), srrctl); in ixgbe_dev_rx_init( ).
Same case is also in the code line: IXGBE_WRITE_REG(hw, IXGBE_VFSRRCTL(i), srrctl); in ixgbevf_dev_rx_init( ).

> > +static int
> > +ixgbe_check_rx_queue_offloads(struct rte_eth_dev *dev, uint64_t
> > +requested) {
> > +	uint64_t port_offloads = dev->data->dev_conf.rxmode.offloads;
> > +	uint64_t queue_supported = ixgbe_get_rx_queue_offloads(dev);
> > +	uint64_t port_supported = ixgbe_get_rx_port_offloads(dev);
> > +
> > +	if ((requested & (queue_supported | port_supported)) != requested)
> > +		return 0;
> > +
> > +	if ((port_offloads ^ requested) & port_supported)
> 
> Could you explain a bit more what are you cheking here?
> As I can see:
>  (port_offloads ^ requested) - that's a diff between already set and newly
> requested offloads.
> Then you check if that diff consists of supported by port offloads, and if yes
> you return an error?
> Konstantin
> 
This function is similar to mlx4_check_rx_queue_offloads() in mlx4 driver.
As the git log message in the commit ce17eddefc20285bbfe575bdc07f42f0b20f34cb say
that a per port capability should has same setting (enabling or disabling) on both port
configuration via rte_eth_dev_configure( ) and queue configuration via rte_eth_rx_queue_setup( ).
This function check if this requirement is matched or not.
It also check offloading request is supported as a per port or a per queue capability or not.
If above checking is pass, it return 1 else return 0.