napi_build_skb() reuses NAPI skbuff_head cache in order to save some
cycles on freeing/allocating skbuff_heads on every new Rx or completed
Tx.
Use napi_consume_skb() to feed the cache with skbuff_heads of completed
Tx. The budget parameter is added to indicate NAPI context, as a value
of zero can be passed in the case of netpoll.
NAT performance results on BT Home Hub 5A (kernel 5.15.45, mtu 1500):
Fast path (Software Flow Offload):
Up Down
Before 702.4 719.3
After 707.3 739.9
Slow path:
Up Down
Before 91.8 184.1
After 92.0 185.7
Signed-off-by: Aleksander Jan Bajkowski <[email protected]>
Acked-by: Hauke Mehrtens <[email protected]>
---
drivers/net/ethernet/lantiq_xrx200.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c
index 57f27cc7724e..13899720423f 100644
--- a/drivers/net/ethernet/lantiq_xrx200.c
+++ b/drivers/net/ethernet/lantiq_xrx200.c
@@ -239,7 +239,7 @@ static int xrx200_hw_receive(struct xrx200_chan *ch)
return ret;
}
- skb = build_skb(buf, priv->rx_skb_size);
+ skb = napi_build_skb(buf, priv->rx_skb_size);
if (!skb) {
skb_free_frag(buf);
net_dev->stats.rx_dropped++;
@@ -328,7 +328,7 @@ static int xrx200_tx_housekeeping(struct napi_struct *napi, int budget)
pkts++;
bytes += skb->len;
ch->skb[ch->tx_free] = NULL;
- consume_skb(skb);
+ napi_consume_skb(skb, budget);
memset(&ch->dma.desc_base[ch->tx_free], 0,
sizeof(struct ltq_dma_desc));
ch->tx_free++;
--
2.30.2
On Sun, 28 Aug 2022 21:19:31 +0200 Aleksander Jan Bajkowski wrote:
> @@ -239,7 +239,7 @@ static int xrx200_hw_receive(struct xrx200_chan *ch)
> return ret;
> }
>
> - skb = build_skb(buf, priv->rx_skb_size);
> + skb = napi_build_skb(buf, priv->rx_skb_size);
This gets called on MTU change, outside of softirq context, no?