net: thunderx: Wakeup TXQ only if CQE_TX are processed

Previously TXQ is wakedup whenever napi is executed
and irrespective of if any CQE_TX are processed or not.
Added 'txq_stop' and 'txq_wake' counters to aid in debugging
if there are any future issues.

Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@caviumnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/cavium/thunder/nic.h b/drivers/net/ethernet/cavium/thunder/nic.h
index dda8a02..a0be076 100644 (file)
--- a/drivers/net/ethernet/cavium/thunder/nic.h
+++ b/drivers/net/ethernet/cavium/thunder/nic.h
@@ -216,8 +216,9 @@ struct nicvf_drv_stats {
        /* Tx */
        u64 tx_frames_ok;
        u64 tx_drops;
-       u64 tx_busy;
        u64 tx_tso;
+       u64 txq_stop;
+       u64 txq_wake;
 };
 
 struct nicvf {

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_ethtool.c b/drivers/net/ethernet/cavium/thunder/nicvf_ethtool.c
index b22dee6..a4228e6 100644 (file)
--- a/drivers/net/ethernet/cavium/thunder/nicvf_ethtool.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_ethtool.c
@@ -66,9 +66,10 @@ static const struct nicvf_stat nicvf_drv_stats[] = {
        NICVF_DRV_STAT(rx_frames_jumbo),
        NICVF_DRV_STAT(rx_drops),
        NICVF_DRV_STAT(tx_frames_ok),
-       NICVF_DRV_STAT(tx_busy),
        NICVF_DRV_STAT(tx_tso),
        NICVF_DRV_STAT(tx_drops),
+       NICVF_DRV_STAT(txq_stop),
+       NICVF_DRV_STAT(txq_wake),
 };
 
 static const struct nicvf_stat nicvf_queue_stats[] = {

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index 2890cd6..422d46e 100644 (file)
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -477,12 +477,13 @@ static void nicvf_rcv_pkt_handler(struct net_device *netdev,
 static int nicvf_cq_intr_handler(struct net_device *netdev, u8 cq_idx,
                                 struct napi_struct *napi, int budget)
 {
-       int processed_cqe, work_done = 0;
+       int processed_cqe, work_done = 0, tx_done = 0;
        int cqe_count, cqe_head;
        struct nicvf *nic = netdev_priv(netdev);
        struct queue_set *qs = nic->qs;
        struct cmp_queue *cq = &qs->cq[cq_idx];
        struct cqe_rx_t *cq_desc;
+       struct netdev_queue *txq;
 
        spin_lock_bh(&cq->lock);
 loop:
@@ -497,8 +498,8 @@ loop:
        cqe_head = nicvf_queue_reg_read(nic, NIC_QSET_CQ_0_7_HEAD, cq_idx) >> 9;
        cqe_head &= 0xFFFF;
 
-       netdev_dbg(nic->netdev, "%s cqe_count %d cqe_head %d\n",
-                  __func__, cqe_count, cqe_head);
+       netdev_dbg(nic->netdev, "%s CQ%d cqe_count %d cqe_head %d\n",
+                  __func__, cq_idx, cqe_count, cqe_head);
        while (processed_cqe < cqe_count) {
                /* Get the CQ descriptor */
                cq_desc = (struct cqe_rx_t *)GET_CQ_DESC(cq, cqe_head);
@@ -512,8 +513,8 @@ loop:
                        break;
                }
 
-               netdev_dbg(nic->netdev, "cq_desc->cqe_type %d\n",
-                          cq_desc->cqe_type);
+               netdev_dbg(nic->netdev, "CQ%d cq_desc->cqe_type %d\n",
+                          cq_idx, cq_desc->cqe_type);
                switch (cq_desc->cqe_type) {
                case CQE_TYPE_RX:
                        nicvf_rcv_pkt_handler(netdev, napi, cq,
@@ -523,6 +524,7 @@ loop:
                case CQE_TYPE_SEND:
                        nicvf_snd_pkt_handler(netdev, cq,
                                              (void *)cq_desc, CQE_TYPE_SEND);
+                       tx_done++;
                break;
                case CQE_TYPE_INVALID:
                case CQE_TYPE_RX_SPLIT:
@@ -533,8 +535,9 @@ loop:
                }
                processed_cqe++;
        }
-       netdev_dbg(nic->netdev, "%s processed_cqe %d work_done %d budget %d\n",
-                  __func__, processed_cqe, work_done, budget);
+       netdev_dbg(nic->netdev,
+                  "%s CQ%d processed_cqe %d work_done %d budget %d\n",
+                  __func__, cq_idx, processed_cqe, work_done, budget);
 
        /* Ring doorbell to inform H/W to reuse processed CQEs */
        nicvf_queue_reg_write(nic, NIC_QSET_CQ_0_7_DOOR,
@@ -544,6 +547,19 @@ loop:
                goto loop;
 
 done:
+       /* Wakeup TXQ if its stopped earlier due to SQ full */
+       if (tx_done) {
+               txq = netdev_get_tx_queue(netdev, cq_idx);
+               if (netif_tx_queue_stopped(txq)) {
+                       netif_tx_wake_queue(txq);
+                       nic->drv_stats.txq_wake++;
+                       if (netif_msg_tx_err(nic))
+                               netdev_warn(netdev,
+                                           "%s: Transmit queue wakeup SQ%d\n",
+                                           netdev->name, cq_idx);
+               }
+       }
+
        spin_unlock_bh(&cq->lock);
        return work_done;
 }
@@ -555,15 +571,10 @@ static int nicvf_poll(struct napi_struct *napi, int budget)
        struct net_device *netdev = napi->dev;
        struct nicvf *nic = netdev_priv(netdev);
        struct nicvf_cq_poll *cq;
-       struct netdev_queue *txq;
 
        cq = container_of(napi, struct nicvf_cq_poll, napi);
        work_done = nicvf_cq_intr_handler(netdev, cq->cq_idx, napi, budget);
 
-       txq = netdev_get_tx_queue(netdev, cq->cq_idx);
-       if (netif_tx_queue_stopped(txq))
-               netif_tx_wake_queue(txq);
-
        if (work_done < budget) {
                /* Slow packet rate, exit polling */
                napi_complete(napi);
@@ -836,7 +847,7 @@ static netdev_tx_t nicvf_xmit(struct sk_buff *skb, struct net_device *netdev)
 
        if (!nicvf_sq_append_skb(nic, skb) && !netif_tx_queue_stopped(txq)) {
                netif_tx_stop_queue(txq);
-               nic->drv_stats.tx_busy++;
+               nic->drv_stats.txq_stop++;
                if (netif_msg_tx_err(nic))
                        netdev_warn(netdev,
                                    "%s: Transmit ring full, stopping SQ%d\n",
@@ -989,6 +1000,9 @@ int nicvf_open(struct net_device *netdev)
        for (qidx = 0; qidx < qs->rbdr_cnt; qidx++)
                nicvf_enable_intr(nic, NICVF_INTR_RBDR, qidx);
 
+       nic->drv_stats.txq_stop = 0;
+       nic->drv_stats.txq_wake = 0;
+
        netif_carrier_on(netdev);
        netif_tx_start_all_queues(netdev);