[PATCH 2/2] brcmfmac: Set pacing shift before transmitting skb to bus

[Wright Feng <wright.feng@cypress.com>]

Linux 3.6 introduces TSQ which has a per socket threshold for TCP Tx
packet to reduce latency. In flow control mode, host driver enqueues skb
in hanger and TCP doesn't push new skb frees until host frees the skb when
receiving fwstatus event. So set pacing shift 8 to send them as a single
large aggregate frame to the bus layer.

43455 TX TCP throughput in FC mode 2 on Linux 5.4.18
sk_pacing_shift : Throughput
10: 190 Mbps
 9: 216 Mbps
 8: 233 Mbps (Max throughput)
 7: 233 Mpbs

Signed-off-by: Wright Feng <wright.feng@cypress.com>
Signed-off-by: Chi-hsien Lin <chi-hsien.lin@cypress.com>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
index c88655acc78c..f89010a81ffb 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
@@ -352,6 +352,9 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
 	if ((skb->priority == 0) || (skb->priority > 7))
 		skb->priority = cfg80211_classify8021d(skb, NULL);
 
+	/* set pacing shift for packet aggregation */
+	sk_pacing_shift_update(skb->sk, 8);
+
 	ret = brcmf_proto_tx_queue_data(drvr, ifp->ifidx, skb);
 	if (ret < 0)
 		brcmf_txfinalize(ifp, skb, false);
-- 
2.25.0