MMIO reads for remaining packets in queue occur (at least)twice per
invocation of netsec_process_rx(). We can use the packet descriptor to
identify if it's owned by the hardware and break out, avoiding the more
expensive MMIO read operations. This has a ~2% increase on the pps of the
Rx path when tested with 64byte packets
Signed-off-by: Ilias Apalodimas <ilias.apalodi...@linaro.org>
---
drivers/net/ethernet/socionext/netsec.c | 19 +++++--------------
1 file changed, 5 insertions(+), 14 deletions(-)
diff --git a/drivers/net/ethernet/socionext/netsec.c
b/drivers/net/ethernet/socionext/netsec.c
index 01589b6..ae32909 100644
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -657,8 +657,6 @@ static struct sk_buff *netsec_get_rx_pkt_data(struct
netsec_priv *priv,
/* move tail ahead */
dring->tail = (dring->tail + 1) % DESC_NUM;
- dring->pkt_cnt--;
-
return skb;
}
@@ -731,25 +729,18 @@ static int netsec_process_rx(struct netsec_priv *priv,
int budget)
struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
struct net_device *ndev = priv->ndev;
struct netsec_rx_pkt_info rx_info;
- int done = 0, rx_num = 0;
+ int done = 0;
struct netsec_desc desc;
struct sk_buff *skb;
u16 len;
while (done < budget) {
- if (!rx_num) {
- rx_num = netsec_read(priv, NETSEC_REG_NRM_RX_PKTCNT);
- dring->pkt_cnt += rx_num;
-
- /* move head 'rx_num' */
- dring->head = (dring->head + rx_num) % DESC_NUM;
+ u16 idx = dring->tail;
+ struct netsec_de *de = dring->vaddr + (DESC_SZ * idx);
- rx_num = dring->pkt_cnt;
- if (!rx_num)
- break;
- }
+ if (de->attr & (1U << NETSEC_RX_PKT_OWN_FIELD))
+ break;
done++;
- rx_num--;
skb = netsec_get_rx_pkt_data(priv, &rx_info, &desc, &len);
if (unlikely(!skb) || rx_info.err_flag) {
netif_err(priv, drv, priv->ndev,
--
2.7.4
