[PATCH 3/9] net: thunderx: Optimize CQE_TX handling

From: sunil . kovvuri
Date: Tue May 02 2017 - 09:09:47 EST

From: Sunil Goutham <sgoutham@xxxxxxxxxx>

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@xxxxxxxxxx>
---
drivers/net/ethernet/cavium/thunder/nicvf_main.c | 44 +++++++++++-----------
drivers/net/ethernet/cavium/thunder/nicvf_queues.c | 5 ---
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 81a2fcb..0d79894 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 @@ static int nicvf_cq_intr_handler(struct net_device *netdev, u8 cq_idx,
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 @@ static int nicvf_cq_intr_handler(struct net_device *netdev, u8 cq_idx,
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 @@ static int nicvf_cq_intr_handler(struct net_device *netdev, u8 cq_idx,
}
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 @@ static int nicvf_cq_intr_handler(struct net_device *netdev, u8 cq_idx,
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 dfc85a1..90c5bc7d 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;
--
2.7.4