[RFC PATCH net-next 2/8] sfc: batch up RX delivery on EF10

[Edward Cree]

Improves packet rate of 1-byte UDP receives by 10%.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 drivers/net/ethernet/sfc/ef10.c       | 9 +++++++++
 drivers/net/ethernet/sfc/efx.c        | 2 ++
 drivers/net/ethernet/sfc/net_driver.h | 3 +++
 drivers/net/ethernet/sfc/rx.c         | 7 ++++++-
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 98d33d4..e348f8f 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -2656,6 +2656,7 @@ static int efx_ef10_ev_process(struct efx_channel 
*channel, int quota)
 {
        struct efx_nic *efx = channel->efx;
        efx_qword_t event, *p_event;
+       struct sk_buff_head rx_list;
        unsigned int read_ptr;
        int ev_code;
        int tx_descs = 0;
@@ -2664,6 +2665,11 @@ static int efx_ef10_ev_process(struct efx_channel 
*channel, int quota)
        if (quota <= 0)
                return spent;
 
+       /* Prepare the batch receive list */
+       EFX_BUG_ON_PARANOID(channel->rx_list != NULL);
+       channel->rx_list = &rx_list;
+       __skb_queue_head_init(channel->rx_list);
+
        read_ptr = channel->eventq_read_ptr;
 
        for (;;) {
@@ -2724,6 +2730,9 @@ static int efx_ef10_ev_process(struct efx_channel 
*channel, int quota)
        }
 
 out:
+       /* Receive any packets we queued up */
+       netif_receive_skb_list(channel->rx_list);
+       channel->rx_list = NULL;
        channel->eventq_read_ptr = read_ptr;
        return spent;
 }
diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 0705ec86..e004c0b 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -527,6 +527,8 @@ static int efx_probe_channel(struct efx_channel *channel)
                        goto fail;
        }
 
+       channel->rx_list = NULL;
+
        return 0;
 
 fail:
diff --git a/drivers/net/ethernet/sfc/net_driver.h 
b/drivers/net/ethernet/sfc/net_driver.h
index 38c4223..d969c85 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -418,6 +418,7 @@ enum efx_sync_events_state {
  *     __efx_rx_packet(), or zero if there is none
  * @rx_pkt_index: Ring index of first buffer for next packet to be delivered
  *     by __efx_rx_packet(), if @rx_pkt_n_frags != 0
+ * @rx_list: list of SKBs from current RX, awaiting processing
  * @rx_queue: RX queue for this channel
  * @tx_queue: TX queues for this channel
  * @sync_events_state: Current state of sync events on this channel
@@ -462,6 +463,8 @@ struct efx_channel {
        unsigned int rx_pkt_n_frags;
        unsigned int rx_pkt_index;
 
+       struct sk_buff_head *rx_list;
+
        struct efx_rx_queue rx_queue;
        struct efx_tx_queue tx_queue[EFX_TXQ_TYPES];
 
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index 8956995..025e387 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -642,7 +642,12 @@ static void efx_rx_deliver(struct efx_channel *channel, u8 
*eh,
                        return;
 
        /* Pass the packet up */
-       netif_receive_skb(skb);
+       if (channel->rx_list != NULL)
+               /* Add to list, will pass up later */
+               __skb_queue_tail(channel->rx_list, skb);
+       else
+               /* No list, so pass it up now */
+               netif_receive_skb(skb);
 }
 
 /* Handle a received packet.  Second half: Touches packet payload. */