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

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

Hi, Konstantin
Thanks for your patient guidance!
> 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( ).
> 
> Yes, HW can enable/disable it on a per queue basis.
> Though it affects rx function selection, and as right now we have one rx
> function per device - That's why it looks to me more like a per port offload.
> Though I believe these days ixgbe PMD doesn't support it properly anyway
> (we always set rxd.hdr_addr to zero) - so probably better to remove it at all.
> 
Yes, rx function is related with offloading.
I'll remove this header split capability in my next patch set.

> >
> > > > +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.
> 
> Ok, let be more specific here.
> Let say:
> requested == DEV_RX_OFFLOAD_VLAN_STRIP;
> port_offloads == DEV_RX_OFFLOAD_IPV4_CKSUM; port_supported =
> (DEV_RX_OFFLOAD_IPV4_CKSUM  |
> 		   DEV_RX_OFFLOAD_UDP_CKSUM   |
> 		   DEV_RX_OFFLOAD_TCP_CKSUM   |
> 		   DEV_RX_OFFLOAD_CRC_STRIP   |
> 		   DEV_RX_OFFLOAD_JUMBO_FRAME |
> 		   DEV_RX_OFFLOAD_SCATTER);
> 
> (port_offloads ^ requested) == DEV_RX_OFFLOAD_VLAN_STRIP |
> DEV_RX_OFFLOAD_IPV4_CKSUM; (port_offloads ^ requested) &
> port_supported == DEV_RX_OFFLOAD_IPV4_CKSUM; And that function will
> return failure, while as I understand it shouldn't - requested queue offload is
> valid.
> 
> Konstantin

I'd like to list the git message of commit ce17eddefc20285bbfe575bdc07f42f0b20f34cb which 
has been submitted by Shahaf Shuler and already been accepted.
SHA-1: ce17eddefc20285bbfe575bdc07f42f0b20f34cb

* ethdev: introduce Rx queue offloads API

Introduce a new API to configure Rx offloads.

In the new API, offloads are divided into per-port and per-queue
offloads. The PMD reports capability for each of them.
Offloads are enabled using the existing DEV_RX_OFFLOAD_* flags.
To enable per-port offload, the offload should be set on both device
configuration and queue configuration. To enable per-queue offload, the
offloads can be set only on queue configuration.

Applications should set the ignore_offload_bitfield bit on rxmode
structure in order to move to the new API.

The old Rx offloads API is kept for the meanwhile, in order to enable a
smooth transition for PMDs and application to the new API.

Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

In your example, IPV4_CKSUM is a per port offloading, it is
Enabled in port_offloads to rte_eth_dev_configure(), and it
Should also be enabled in requested to rte_eth_rx_queue_setup( ).
So your example fails in this checking.

This function is very similar with priv_is_rx_queue_offloads_allowed( ) in /net/mlx5/mlx5_rxq.c
In the patch http://dpdk.org/dev/patchwork/patch/33386/ which has already been accepted.