ath10k: enable napi on RX path for sdio

For tcp RX, the quantity of tcp acks to remote is 1/2 of the quantity
of tcp data from remote, then it will have many small length packets
on TX path of sdio bus, then it reduce the RX packets's bandwidth of
tcp.

This patch enable napi on RX path, then the RX packet of tcp will not
feed to tcp stack immeditely from mac80211 since GRO is enabled by
default, it will feed to tcp stack after napi complete, if rx bundle
is enabled, then it will feed to tcp stack one time for each bundle
of RX. For example, RX bundle size is 32, then tcp stack will receive
one large length packet, its length is neary 1500*32, then tcp stack
will send a tcp ack for this large packet, this will reduce the tcp
acks ratio from 1/2 to 1/32. This results in significant performance
improvement for tcp RX.

Tcp rx throughout is 240Mbps without this patch, and it arrive 390Mbps
with this patch. The cpu usage has no obvious difference with and
without NAPI.

call stack for each RX packet on GRO path:
(skb length is about 1500 bytes)
  skb_gro_receive ([kernel.kallsyms])
  tcp4_gro_receive ([kernel.kallsyms])
  inet_gro_receive ([kernel.kallsyms])
  dev_gro_receive ([kernel.kallsyms])
  napi_gro_receive ([kernel.kallsyms])
  ieee80211_deliver_skb ([mac80211])
  ieee80211_rx_handlers ([mac80211])
  ieee80211_prepare_and_rx_handle ([mac80211])
  ieee80211_rx_napi ([mac80211])
  ath10k_htt_rx_proc_rx_ind_hl ([ath10k_core])
  ath10k_htt_rx_pktlog_completion_handler ([ath10k_core])
  ath10k_sdio_napi_poll ([ath10k_sdio])
  net_rx_action ([kernel.kallsyms])
  softirqentry_text_start ([kernel.kallsyms])
  do_softirq ([kernel.kallsyms])

call stack for napi complete and send tcp ack from tcp stack:
(skb length is about 1500*32 bytes)
 _tcp_ack_snd_check ([kernel.kallsyms])
 tcp_v4_do_rcv ([kernel.kallsyms])
 tcp_v4_rcv ([kernel.kallsyms])
 local_deliver_finish ([kernel.kallsyms])
 ip_local_deliver ([kernel.kallsyms])
 ip_rcv_finish ([kernel.kallsyms])
 ip_rcv ([kernel.kallsyms])
 netif_receive_skb_core ([kernel.kallsyms])
 netif_receive_skb_one_core([kernel.kallsyms])
 netif_receive_skb ([kernel.kallsyms])
 netif_receive_skb_internal ([kernel.kallsyms])
 napi_gro_complete ([kernel.kallsyms])
 napi_gro_flush ([kernel.kallsyms])
 napi_complete_done ([kernel.kallsyms])
 ath10k_sdio_napi_poll ([ath10k_sdio])
 net_rx_action ([kernel.kallsyms])
 __softirqentry_text_start ([kernel.kallsyms])
 do_softirq ([kernel.kallsyms])

Tested with QCA6174 SDIO with firmware
WLAN.RMH.4.4.1-00017-QCARMSWP-1.

Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath10k/htt.h b/drivers/net/wireless/ath/ath10k/htt.h
index 30c080094af1..4a12564fc30e 100644
--- a/drivers/net/wireless/ath/ath10k/htt.h
+++ b/drivers/net/wireless/ath/ath10k/htt.h
@@ -1869,6 +1869,8 @@ struct ath10k_htt {
 	struct ath10k *ar;
 	enum ath10k_htc_ep_id eid;
 
+	struct sk_buff_head rx_indication_head;
+
 	u8 target_version_major;
 	u8 target_version_minor;
 	struct completion target_version_received;
@@ -2283,6 +2285,7 @@ int ath10k_htt_mgmt_tx(struct ath10k_htt *htt, struct sk_buff *msdu);
 void ath10k_htt_rx_pktlog_completion_handler(struct ath10k *ar,
 					     struct sk_buff *skb);
 int ath10k_htt_txrx_compl_task(struct ath10k *ar, int budget);
+int ath10k_htt_rx_hl_indication(struct ath10k *ar, int budget);
 void ath10k_htt_set_tx_ops(struct ath10k_htt *htt);
 void ath10k_htt_set_rx_ops(struct ath10k_htt *htt);
 #endif