ath11k: optimize RX path latency

This patch drops ath11k_hal_rx_parse_dst_ring_desc(). This function was
creating a huge amount of load, which lead to a signifcant latency delay
when processing data in the RX path.

Pegging the processing on a specific core and running perf --top we get
the following output when running HE80 at a fixed bandwidth of 1gbit.

with patch
    19.19%  [ath11k]       [k] ath11k_dp_process_rx
     5.02%  [ath11k]       [k] ath11k_dp_rx_tid_del_func
     4.39%  [kernel]       [k] v7_dma_inv_range
     4.15%  [kernel]       [k] __slab_alloc.constprop.1
     4.03%  [kernel]       [k] dev_gro_receive
     3.86%  [kernel]       [k] tcp_gro_receive
     3.07%  [ip_tables]    [k] ipt_do_table
     2.96%  [kernel]       [k] dma_cache_maint_page

without patch
    21.64%  [ath11k]       [k] ath11k_hal_rx_parse_dst_ring_desc
    10.80%  [ath11k]       [k] ath11k_dp_process_rx
     3.77%  [kernel]       [k] v7_dma_inv_range
     3.48%  [kernel]       [k] dev_gro_receive
     3.32%  [ath11k]       [k] ath11k_dp_rx_tid_del_func
     3.17%  [mac80211]     [k] ieee80211_rx_napi
     2.70%  [kernel]       [k] dma_cache_maint_page
     2.65%  [mac80211]     [k] ieee80211_sta_ps_transition

When removing the the bandwidth limit and rerunning the test we see an
overall throughput improvement of 3-400mbit when running 4x4 HE80.

Signed-off-by: Shashidhar Lakkavalli <slakkavalli@datto.com>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

1 files changed, 4 insertions, 45 deletions

diff --git a/drivers/net/wireless/ath/ath11k/hal_rx.c b/drivers/net/wireless/ath/ath11k/hal_rx.c
index 2de4b388db20..6168a4eb0c0b 100644
--- a/drivers/net/wireless/ath/ath11k/hal_rx.c
+++ b/drivers/net/wireless/ath/ath11k/hal_rx.c
@@ -290,7 +290,7 @@ void ath11k_hal_rx_buf_addr_info_get(void *desc, dma_addr_t *paddr,
 }
 
 void ath11k_hal_rx_msdu_link_info_get(void *link_desc, u32 *num_msdus,
-				      struct hal_rx_msdu_meta *meta,
+				      u32 *msdu_cookies,
 				      enum hal_rx_buf_return_buf_manager *rbm)
 {
 	struct hal_rx_msdu_link *link = (struct hal_rx_msdu_link *)link_desc;
@@ -311,17 +311,9 @@ void ath11k_hal_rx_msdu_link_info_get(void *link_desc, u32 *num_msdus,
 			*num_msdus = i;
 			break;
 		}
-		meta->msdu_len = FIELD_GET(RX_MSDU_DESC_INFO0_MSDU_LENGTH,
-					   msdu->rx_msdu_info.info0);
-		meta->first = !!(msdu->rx_msdu_info.info0 &
-				 RX_MSDU_DESC_INFO0_FIRST_MSDU_IN_MPDU);
-		meta->last = !!(msdu->rx_msdu_info.info0 &
-				RX_MSDU_DESC_INFO0_LAST_MSDU_IN_MPDU);
-		meta->continuation = !!(msdu->rx_msdu_info.info0 &
-					RX_MSDU_DESC_INFO0_MSDU_CONTINUATION);
-		meta->cookie = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE,
-					 msdu->buf_addr_info.info1);
-		meta++;
+		*msdu_cookies = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE,
+					  msdu->buf_addr_info.info1);
+		msdu_cookies++;
 	}
 }
 
@@ -356,39 +348,6 @@ int ath11k_hal_desc_reo_parse_err(struct ath11k_base *ab, u32 *rx_desc,
 	return 0;
 }
 
-void ath11k_hal_rx_parse_dst_ring_desc(struct ath11k_base *ab, u32 *rx_desc,
-				       struct hal_rx_meta_info *meta_info)
-{
-	struct hal_reo_dest_ring *desc = (struct hal_reo_dest_ring *)rx_desc;
-	struct rx_mpdu_desc *mpdu = &desc->rx_mpdu_info;
-	struct rx_msdu_desc *msdu = &desc->rx_msdu_info;
-	struct hal_rx_mpdu_meta *meta_mpdu = &meta_info->mpdu_meta;
-	struct hal_rx_msdu_meta *meta_msdu = &meta_info->msdu_meta;
-
-	meta_info->push_reason = FIELD_GET(HAL_REO_DEST_RING_INFO0_PUSH_REASON,
-					   desc->info0);
-
-	meta_mpdu->msdu_cnt = FIELD_GET(RX_MPDU_DESC_INFO0_MSDU_COUNT,
-					mpdu->info0);
-	meta_mpdu->seq_num = FIELD_GET(RX_MPDU_DESC_INFO0_SEQ_NUM, mpdu->info0);
-	meta_mpdu->frag = !!(mpdu->info0 & RX_MPDU_DESC_INFO0_FRAG_FLAG);
-	meta_mpdu->retry = !!(mpdu->info0 & RX_MPDU_DESC_INFO0_MPDU_RETRY);
-	meta_mpdu->ampdu = !!(mpdu->info0 & RX_MPDU_DESC_INFO0_AMPDU_FLAG);
-	meta_mpdu->raw = !!(mpdu->info0 & RX_MPDU_DESC_INFO0_RAW_MPDU);
-	meta_mpdu->peer_meta = mpdu->meta_data;
-
-	meta_msdu->cookie = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE,
-				      desc->buf_addr_info.info1);
-	meta_msdu->msdu_len = FIELD_GET(RX_MSDU_DESC_INFO0_MSDU_LENGTH,
-					msdu->info0);
-	meta_msdu->first =
-		!!(msdu->info0 & RX_MSDU_DESC_INFO0_FIRST_MSDU_IN_MPDU);
-	meta_msdu->last =
-		!!(msdu->info0 & RX_MSDU_DESC_INFO0_LAST_MSDU_IN_MPDU);
-	meta_msdu->continuation =
-		!!(msdu->info0 & RX_MSDU_DESC_INFO0_MSDU_CONTINUATION);
-}
-
 int ath11k_hal_wbm_desc_parse_err(struct ath11k_base *ab, void *desc,
 				  struct hal_rx_wbm_rel_info *rel_info)
 {