RE: [PATCH v7 8/8] net/gve: add support for Rx/Tx

["Guo, Junfeng" <junfeng.guo@intel.com>]

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit@amd.com>
> Sent: Friday, October 21, 2022 17:52
> To: Guo, Junfeng <junfeng.guo@intel.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>;
> ferruh.yigit@xilinx.com; Xing, Beilei <beilei.xing@intel.com>
> Cc: dev@dpdk.org; Li, Xiaoyun <xiaoyun.li@intel.com>;
> awogbemila@google.com; Richardson, Bruce
> <bruce.richardson@intel.com>; hemant.agrawal@nxp.com;
> stephen@networkplumber.org; Xia, Chenbo <chenbo.xia@intel.com>;
> Zhang, Helin <helin.zhang@intel.com>
> Subject: Re: [PATCH v7 8/8] net/gve: add support for Rx/Tx
> 
> On 10/21/2022 10:19 AM, Junfeng Guo wrote:
> 
> >
> > Add Rx/Tx of GQI_QPL queue format and GQI_RDA queue format.
> >
> > Signed-off-by: Xiaoyun Li <xiaoyun.li@intel.com>
> > Signed-off-by: Junfeng Guo <junfeng.guo@intel.com>
> 
> <...>
> 
> > +
> > +static inline void
> > +gve_tx_clean_swr_qpl(struct gve_tx_queue *txq)
> > +{
> > +       uint32_t start = txq->sw_ntc;
> > +       uint32_t ntc, nb_clean;
> > +
> > +       ntc = txq->sw_tail;
> > +
> > +       if (ntc == start)
> > +               return;
> > +
> > +       /* if wrap around, free twice. */
> > +       if (ntc < start) {
> > +               nb_clean = txq->nb_tx_desc - start;
> > +               if (nb_clean > GVE_TX_MAX_FREE_SZ)
> > +                       nb_clean = GVE_TX_MAX_FREE_SZ;
> > +               gve_free_bulk_mbuf(&txq->sw_ring[start], nb_clean);
> > +
> > +               txq->sw_nb_free += nb_clean;
> > +               start += nb_clean;
> > +               if (start == txq->nb_tx_desc)
> > +                       start = 0;
> > +               txq->sw_ntc = start;
> > +       }
> > +
> > +       if (ntc > start) {
> > +               nb_clean = ntc - start;
> > +               if (nb_clean > GVE_TX_MAX_FREE_SZ)
> > +                       nb_clean = GVE_TX_MAX_FREE_SZ;
> > +               gve_free_bulk_mbuf(&txq->sw_ring[start], nb_clean);
> > +               txq->sw_nb_free += nb_clean;
> > +               start += nb_clean;
> > +               txq->sw_ntc = start;
> > +       }
> > +}
> 
> [copy/paste from previous version]
> 
> may be can drop the 'if' block, since "ntc == start" and "ntc < start"
> cases already covered.

Yes, this 'if' block is dropped in v7 as suggested. Thanks!

> 
> <...>
> 
> > +uint16_t
> > +gve_tx_burst(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t
> nb_pkts)
> > +{
> > +       struct gve_tx_queue *txq = tx_queue;
> > +
> > +       if (txq->is_gqi_qpl)
> > +               return gve_tx_burst_qpl(tx_queue, tx_pkts, nb_pkts);
> > +
> > +       return gve_tx_burst_ra(tx_queue, tx_pkts, nb_pkts);
> > +}
> > +
> 
> [copy/paste from previous version]
> 
> Can there be mix of queue types?
> If only one queue type is supported in specific config, perhaps burst
> function can be set during configuration, to prevent if check on datapath.
> 
> This is optimization and can be done later, it doesn't have to be in the
> set.

The exact queue type can be fetched from the backend via adminq 
in priv->queue_format. So there won't be mix of the queue types.
Currently, only GQI_QPL and GQI_RDA queue format are supported 
in PMD. Also, only GQI_QPL queue format is in use on GCP since 
GQI_RDA hasn't been released in production.
This part code will be optimized/refactored later when involving 
the queue type DQO_RDA. Thanks!