Re: [dpdk-dev] [PATCH] net/i40e: fix Tx fn selection when using new ethdev offloads

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, May 01, 2018 at 02:24:39PM +0100, Ananyev, Konstantin wrote:
> Hi Bruce,
> 
> > 
> > The Tx function selection code in the driver only used the older txq
> > flags values to check whether the scalar or vector functions should be
> > used. This caused performance regressions with testpmd io-fwd as the
> > scalar path rather than the vector one was being used in the default
> > case. Fix this by changing the code to take account of new offloads and
> > deleting the defines used for the old ones.
> > 
> > Fixes: 7497d3e2f777 ("net/i40e: convert to new Tx offloads API")
> > 
> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> > ---
> >  drivers/net/i40e/i40e_rxtx.c | 45 +++++++++++++++++++++++---------------------
> >  1 file changed, 24 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
> > index ec1ce54ca..c523af575 100644
> > --- a/drivers/net/i40e/i40e_rxtx.c
> > +++ b/drivers/net/i40e/i40e_rxtx.c
> > @@ -40,9 +40,6 @@
> >  /* Base address of the HW descriptor ring should be 128B aligned. */
> >  #define I40E_RING_BASE_ALIGN	128
> > 
> > -#define I40E_SIMPLE_FLAGS ((uint32_t)ETH_TXQ_FLAGS_NOMULTSEGS | \
> > -					ETH_TXQ_FLAGS_NOOFFLOADS)
> > -
> >  #define I40E_TXD_CMD (I40E_TX_DESC_CMD_EOP | I40E_TX_DESC_CMD_RS)
> > 
> >  #ifdef RTE_LIBRTE_IEEE1588
> > @@ -70,6 +67,12 @@
> >  #define I40E_TX_OFFLOAD_NOTSUP_MASK \
> >  		(PKT_TX_OFFLOAD_MASK ^ I40E_TX_OFFLOAD_MASK)
> > 
> > +static const uint64_t i40e_simple_ol_mask = (DEV_TX_OFFLOAD_MULTI_SEGS |
> > +		DEV_TX_OFFLOAD_VLAN_INSERT |
> > +		DEV_TX_OFFLOAD_SCTP_CKSUM |
> > +		DEV_TX_OFFLOAD_UDP_CKSUM |
> > +		DEV_TX_OFFLOAD_TCP_CKSUM);
> > +
> 
> Seems incomplete.
> From i40e_ethdev.c full-featured tx supports:
> dev_info->tx_offload_capa =
>                 DEV_TX_OFFLOAD_VLAN_INSERT |
>                 DEV_TX_OFFLOAD_QINQ_INSERT |
>                 DEV_TX_OFFLOAD_IPV4_CKSUM |
>                 DEV_TX_OFFLOAD_UDP_CKSUM |
>                 DEV_TX_OFFLOAD_TCP_CKSUM |
>                 DEV_TX_OFFLOAD_SCTP_CKSUM |
>                 DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM |
>                 DEV_TX_OFFLOAD_TCP_TSO |
>                 DEV_TX_OFFLOAD_VXLAN_TNL_TSO |
>                 DEV_TX_OFFLOAD_GRE_TNL_TSO |
>                 DEV_TX_OFFLOAD_IPIP_TNL_TSO |
>                 DEV_TX_OFFLOAD_GENEVE_TNL_TSO;
> 
> So we probably need the same here plus multiseg.
> BTW, it is really strange that we don't have multiseg in tx_offload_capa.
> Should be present I think.
> Might be worse to create a new define for it, or just use dev_info->tx_offload_capa directly.
> Konstantin
> 
Thanks, good point, I never thought to check the advertised capabilities. I
just translated what was being used by the old code txq_flags translation 
function. I'll clean this up and do a V2.

/Bruce