RE: [PATCH net-next 2/3] octeon_ep: implement xmit_more in transmit

[Drewek, Wojciech]

> -----Original Message-----
> From: Shinas Rasheed <srasheed@xxxxxxxxxxx>
> Sent: Monday, October 23, 2023 1:45 PM
> To: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: hgani@xxxxxxxxxxx; vimleshk@xxxxxxxxxxx; Gallen, Erwan <egallen@xxxxxxxxxx>; mschmidt <mschmidt@xxxxxxxxxx>;
> pabeni@xxxxxxxxxx; horms@xxxxxxxxxx; kuba@xxxxxxxxxx; davem@xxxxxxxxxxxxx; Shinas Rasheed <srasheed@xxxxxxxxxxx>;
> Veerasenareddy Burru <vburru@xxxxxxxxxxx>; Sathesh Edara <sedara@xxxxxxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>
> Subject: [PATCH net-next 2/3] octeon_ep: implement xmit_more in transmit
> 
> Adds xmit_more handling in tx datapath for octeon_ep pf.

Imperative mode is preferred :)
Besides that:
Reviewed-by: Wojciech Drewek <wojciech.drewek@xxxxxxxxx>

> 
> Signed-off-by: Shinas Rasheed <srasheed@xxxxxxxxxxx>
> ---
>  .../ethernet/marvell/octeon_ep/octep_config.h |  2 +-
>  .../ethernet/marvell/octeon_ep/octep_main.c   | 19 +++++++++++++++----
>  2 files changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_config.h b/drivers/net/ethernet/marvell/octeon_ep/octep_config.h
> index 1622a6ebf036..ed8b1ace56b9 100644
> --- a/drivers/net/ethernet/marvell/octeon_ep/octep_config.h
> +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_config.h
> @@ -15,7 +15,7 @@
>  /* Tx Queue: maximum descriptors per ring */
>  #define OCTEP_IQ_MAX_DESCRIPTORS    1024
>  /* Minimum input (Tx) requests to be enqueued to ring doorbell */
> -#define OCTEP_DB_MIN                1
> +#define OCTEP_DB_MIN                8
>  /* Packet threshold for Tx queue interrupt */
>  #define OCTEP_IQ_INTR_THRESHOLD     0x0
> 
> diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> index bf1e376a4232..730443ba2f5b 100644
> --- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> @@ -818,6 +818,7 @@ static netdev_tx_t octep_start_xmit(struct sk_buff *skb,
>  	struct octep_iq *iq;
>  	skb_frag_t *frag;
>  	u16 nr_frags, si;
> +	int xmit_more;
>  	u16 q_no, wi;
> 
>  	q_no = skb_get_queue_mapping(skb);
> @@ -892,18 +893,28 @@ static netdev_tx_t octep_start_xmit(struct sk_buff *skb,
>  	}
> 
>  	netdev_tx_sent_queue(iq->netdev_q, skb->len);
> +
> +	xmit_more = netdev_xmit_more();
> +
>  	skb_tx_timestamp(skb);
>  	atomic_inc(&iq->instr_pending);
> +	iq->fill_cnt++;
>  	wi++;
>  	if (wi == iq->max_count)
>  		wi = 0;
>  	iq->host_write_index = wi;
> +	if (xmit_more &&
> +	    (atomic_read(&iq->instr_pending) <
> +	     (iq->max_count - OCTEP_WAKE_QUEUE_THRESHOLD)) &&
> +	    iq->fill_cnt < iq->fill_threshold)
> +		return NETDEV_TX_OK;
> +
>  	/* Flush the hw descriptor before writing to doorbell */
>  	wmb();
> -
> -	/* Ring Doorbell to notify the NIC there is a new packet */
> -	writel(1, iq->doorbell_reg);
> -	iq->stats.instr_posted++;
> +	/* Ring Doorbell to notify the NIC of new packets */
> +	writel(iq->fill_cnt, iq->doorbell_reg);
> +	iq->stats.instr_posted += iq->fill_cnt;
> +	iq->fill_cnt = 0;
>  	return NETDEV_TX_OK;
> 
>  dma_map_sg_err:
> --
> 2.25.1
>