On Tue, Oct 22, 2019 at 5:38 PM Zhu Yanjun <yanjun....@oracle.com> wrote:
>
> This change adds support for xmit_more based on the igb commit 6f19e12f6230
> ("igb: flush when in xmit_more mode and under descriptor pressure") and
> commit 6b16f9ee89b8 ("net: move skb->xmit_more hint to softnet data") that
> were made to igb to support this feature. The function netif_xmit_stopped
> is called to check if transmit queue on device is currently unable to send
> to determine if we must write the tail because we can add no further
> buffers.
> When normal packets and/or xmit_more packets fill up tx_desc, it is
> necessary to trigger NIC tx reg.
>
> Tested:
> - pktgen (xmit_more packets) SMP x86_64 ->
> Test command:
> ./pktgen_sample03_burst_single_flow.sh ... -b 8 -n 1000000
> Test results:
> Params:
> ...
> burst: 8
> ...
> Result: OK: 12194004(c12188996+d5007) usec, 1000001 (1500byte,0frags)
> 82007pps 984Mb/sec (984084000bps) errors: 0
>
> - iperf (normal packets) SMP x86_64 ->
> Test command:
> Server: iperf -s
> Client: iperf -c serverip
> Result:
> TCP window size: 85.0 KByte (default)
> ------------------------------------------------------------
> [ ID] Interval Transfer Bandwidth
> [ 3] 0.0-10.0 sec 1.10 GBytes 942 Mbits/sec
>
> CC: Joe Jin <joe....@oracle.com>
> CC: JUNXIAO_BI <junxiao...@oracle.com>
> Reported-and-tested-by: Nan san <nan.1986...@gmail.com>
> Signed-off-by: Zhu Yanjun <yanjun....@oracle.com>
Thanks.
Acked-by: Rain River <rain.1986.08...@gmail.com>
> ---
> V1->V2: use the lower case label.
> ---
> drivers/net/ethernet/nvidia/forcedeth.c | 37
> +++++++++++++++++++++++++++------
> 1 file changed, 31 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/nvidia/forcedeth.c
> b/drivers/net/ethernet/nvidia/forcedeth.c
> index 05d2b47..e2bb0cd 100644
> --- a/drivers/net/ethernet/nvidia/forcedeth.c
> +++ b/drivers/net/ethernet/nvidia/forcedeth.c
> @@ -2225,6 +2225,7 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb,
> struct net_device *dev)
> struct nv_skb_map *prev_tx_ctx;
> struct nv_skb_map *tmp_tx_ctx = NULL, *start_tx_ctx = NULL;
> unsigned long flags;
> + netdev_tx_t ret = NETDEV_TX_OK;
>
> /* add fragments to entries count */
> for (i = 0; i < fragments; i++) {
> @@ -2240,7 +2241,12 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb,
> struct net_device *dev)
> netif_stop_queue(dev);
> np->tx_stop = 1;
> spin_unlock_irqrestore(&np->lock, flags);
> - return NETDEV_TX_BUSY;
> +
> + /* When normal packets and/or xmit_more packets fill up
> + * tx_desc, it is necessary to trigger NIC tx reg.
> + */
> + ret = NETDEV_TX_BUSY;
> + goto txkick;
> }
> spin_unlock_irqrestore(&np->lock, flags);
>
> @@ -2357,8 +2363,14 @@ static netdev_tx_t nv_start_xmit(struct sk_buff *skb,
> struct net_device *dev)
>
> spin_unlock_irqrestore(&np->lock, flags);
>
> - writel(NVREG_TXRXCTL_KICK|np->txrxctl_bits, get_hwbase(dev) +
> NvRegTxRxControl);
> - return NETDEV_TX_OK;
> +txkick:
> + if (netif_queue_stopped(dev) || !netdev_xmit_more()) {
> + u32 txrxctl_kick = NVREG_TXRXCTL_KICK | np->txrxctl_bits;
> +
> + writel(txrxctl_kick, get_hwbase(dev) + NvRegTxRxControl);
> + }
> +
> + return ret;
> }
>
> static netdev_tx_t nv_start_xmit_optimized(struct sk_buff *skb,
> @@ -2381,6 +2393,7 @@ static netdev_tx_t nv_start_xmit_optimized(struct
> sk_buff *skb,
> struct nv_skb_map *start_tx_ctx = NULL;
> struct nv_skb_map *tmp_tx_ctx = NULL;
> unsigned long flags;
> + netdev_tx_t ret = NETDEV_TX_OK;
>
> /* add fragments to entries count */
> for (i = 0; i < fragments; i++) {
> @@ -2396,7 +2409,13 @@ static netdev_tx_t nv_start_xmit_optimized(struct
> sk_buff *skb,
> netif_stop_queue(dev);
> np->tx_stop = 1;
> spin_unlock_irqrestore(&np->lock, flags);
> - return NETDEV_TX_BUSY;
> +
> + /* When normal packets and/or xmit_more packets fill up
> + * tx_desc, it is necessary to trigger NIC tx reg.
> + */
> + ret = NETDEV_TX_BUSY;
> +
> + goto txkick;
> }
> spin_unlock_irqrestore(&np->lock, flags);
>
> @@ -2542,8 +2561,14 @@ static netdev_tx_t nv_start_xmit_optimized(struct
> sk_buff *skb,
>
> spin_unlock_irqrestore(&np->lock, flags);
>
> - writel(NVREG_TXRXCTL_KICK|np->txrxctl_bits, get_hwbase(dev) +
> NvRegTxRxControl);
> - return NETDEV_TX_OK;
> +txkick:
> + if (netif_queue_stopped(dev) || !netdev_xmit_more()) {
> + u32 txrxctl_kick = NVREG_TXRXCTL_KICK | np->txrxctl_bits;
> +
> + writel(txrxctl_kick, get_hwbase(dev) + NvRegTxRxControl);
> + }
> +
> + return ret;
> }
>
> static inline void nv_tx_flip_ownership(struct net_device *dev)
> --
> 2.7.4
>
