net: thunderx: Optimize CQE_TX handling

Optimized CQE handling with below changes
- Feeing descriptors back to SQ in bulk i.e once per NAPI
  instance instead for every CQE_TX, this will reduce number
  of atomic updates to 'sq->free_cnt'.
- Checking errors in CQE_TX and CQE_RX before calling appropriate
  fn()s to update error stats i.e reduce branching.

Also removed debug messages in packet handling path which otherwise
causes issues if DEBUG is enabled.

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

2 files changed, 21 insertions, 28 deletions

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index 81a2fcb3cb1b..0d79894400ab 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -498,7 +498,7 @@ static int nicvf_init_resources(struct nicvf *nic)
 
 static void nicvf_snd_pkt_handler(struct net_device *netdev,
                                   struct cqe_send_t *cqe_tx,
-                                  int cqe_type, int budget,
+                                  int budget, int *subdesc_cnt,
                                   unsigned int *tx_pkts, unsigned int *tx_bytes)
 {
         struct sk_buff *skb = NULL;
@@ -513,12 +513,10 @@ static void nicvf_snd_pkt_handler(struct net_device *netdev,
         if (hdr->subdesc_type != SQ_DESC_TYPE_HEADER)
                 return;
 
-        netdev_dbg(nic->netdev,
-                   "%s Qset #%d SQ #%d SQ ptr #%d subdesc count %d\n",
-                   __func__, cqe_tx->sq_qs, cqe_tx->sq_idx,
-                   cqe_tx->sqe_ptr, hdr->subdesc_cnt);
+        /* Check for errors */
+        if (cqe_tx->send_status)
+                nicvf_check_cqe_tx_errs(nic->pnicvf, cqe_tx);
 
-        nicvf_check_cqe_tx_errs(nic, cqe_tx);
         skb = (struct sk_buff *)sq->skbuff[cqe_tx->sqe_ptr];
         if (skb) {
                 /* Check for dummy descriptor used for HW TSO offload on 88xx */
@@ -528,12 +526,12 @@ static void nicvf_snd_pkt_handler(struct net_device *netdev,
                          (struct sq_hdr_subdesc *)GET_SQ_DESC(sq, hdr->rsvd2);
                         nicvf_unmap_sndq_buffers(nic, sq, hdr->rsvd2,
                                                  tso_sqe->subdesc_cnt);
-                        nicvf_put_sq_desc(sq, tso_sqe->subdesc_cnt + 1);
+                        *subdesc_cnt += tso_sqe->subdesc_cnt + 1;
                 } else {
                         nicvf_unmap_sndq_buffers(nic, sq, cqe_tx->sqe_ptr,
                                                  hdr->subdesc_cnt);
                 }
-                nicvf_put_sq_desc(sq, hdr->subdesc_cnt + 1);
+                *subdesc_cnt += hdr->subdesc_cnt + 1;
                 prefetch(skb);
                 (*tx_pkts)++;
                 *tx_bytes += skb->len;
@@ -544,7 +542,7 @@ static void nicvf_snd_pkt_handler(struct net_device *netdev,
                  * a SKB attached, so just free SQEs here.
                  */
                 if (!nic->hw_tso)
-                        nicvf_put_sq_desc(sq, hdr->subdesc_cnt + 1);
+                        *subdesc_cnt += hdr->subdesc_cnt + 1;
         }
 }
 
@@ -595,9 +593,11 @@ static void nicvf_rcv_pkt_handler(struct net_device *netdev,
         }
 
         /* Check for errors */
-        err = nicvf_check_cqe_rx_errs(nic, cqe_rx);
-        if (err && !cqe_rx->rb_cnt)
-                return;
+        if (cqe_rx->err_level || cqe_rx->err_opcode) {
+                err = nicvf_check_cqe_rx_errs(nic, cqe_rx);
+                if (err && !cqe_rx->rb_cnt)
+                        return;
+        }
 
         skb = nicvf_get_rcv_skb(snic, cqe_rx);
         if (!skb) {
@@ -646,6 +646,7 @@ static int nicvf_cq_intr_handler(struct net_device *netdev, u8 cq_idx,
 {
         int processed_cqe, work_done = 0, tx_done = 0;
         int cqe_count, cqe_head;
+        int subdesc_cnt = 0;
         struct nicvf *nic = netdev_priv(netdev);
         struct queue_set *qs = nic->qs;
         struct cmp_queue *cq = &qs->cq[cq_idx];
@@ -667,8 +668,6 @@ 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 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);
@@ -682,17 +681,15 @@ loop:
                         break;
                 }
 
-                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_desc);
                         work_done++;
                 break;
                 case CQE_TYPE_SEND:
-                        nicvf_snd_pkt_handler(netdev,
-                                              (void *)cq_desc, CQE_TYPE_SEND,
-                                              budget, &tx_pkts, &tx_bytes);
+                        nicvf_snd_pkt_handler(netdev, (void *)cq_desc,
+                                              budget, &subdesc_cnt,
+                                              &tx_pkts, &tx_bytes);
                         tx_done++;
                 break;
                 case CQE_TYPE_INVALID:
@@ -704,9 +701,6 @@ loop:
                 }
                 processed_cqe++;
         }
-        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,
@@ -716,8 +710,12 @@ loop:
                 goto loop;
 
 done:
-        /* Wakeup TXQ if its stopped earlier due to SQ full */
         sq = &nic->qs->sq[cq_idx];
+        /* Update SQ's descriptor free count */
+        if (subdesc_cnt)
+                nicvf_put_sq_desc(sq, subdesc_cnt);
+
+        /* Wakeup TXQ if its stopped earlier due to SQ full */
         if (tx_done ||
             (atomic_read(&sq->free_cnt) >= MIN_SQ_DESC_PER_PKT_XMIT)) {
                 netdev = nic->pnicvf->netdev;
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
index dfc85a169127..90c5bc7d7344 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
@@ -1640,9 +1640,6 @@ void nicvf_update_sq_stats(struct nicvf *nic, int sq_idx)
 /* Check for errors in the receive cmp.queue entry */
 int nicvf_check_cqe_rx_errs(struct nicvf *nic, struct cqe_rx_t *cqe_rx)
 {
-        if (!cqe_rx->err_level && !cqe_rx->err_opcode)
-                return 0;
-
         if (netif_msg_rx_err(nic))
                 netdev_err(nic->netdev,
                            "%s: RX error CQE err_level 0x%x err_opcode 0x%x\n",
@@ -1731,8 +1728,6 @@ int nicvf_check_cqe_rx_errs(struct nicvf *nic, struct cqe_rx_t *cqe_rx)
 int nicvf_check_cqe_tx_errs(struct nicvf *nic, struct cqe_send_t *cqe_tx)
 {
         switch (cqe_tx->send_status) {
-        case CQ_TX_ERROP_GOOD:
-                return 0;
         case CQ_TX_ERROP_DESC_FAULT:
                 this_cpu_inc(nic->drv_stats->tx_desc_fault);
                 break;