Merge branch 'aquantia-rx-perf'

Igor Russkikh says:

====================
net: aquantia: RX performance optimization patches

Here is a set of patches targeting for performance improvement
on various platforms and protocols.

Our main target was rx performance on iommu systems, notably
NVIDIA Jetson TX2 and NVIDIA Xavier platforms.

We introduce page reuse strategy to better deal with iommu dma mapping costs.
With it we see 80-90% of page reuse under some test configurations on UDP traffic.

This shows good improvements on other systems with IOMMU hardware, like
AMD Ryzen.

We've also improved TCP LRO configuration parameters, allowing packets to better
coalesce.

Page reuse tests were carried out using iperf3, iperf2, netperf and pktgen.
Mainly on UDP traffic, with various packet lengths.

Jetson TX2, UDP, Default MTU:
RX Lost Datagrams
  Before: Max: 69%  Min: 68% Avg: 68.5%
  After:  Max: 41%  Min: 38% Avg: 39.2%
Maximum throughput
  Before: 1.27 Gbits/sec
  After:  2.41 Gbits/sec

AMD Ryzen 5 2400G, UDP, Default MTU:
RX Lost Datagrams
  Before:  Max: 12%  Min: 4.5% Avg: 7.17%
  After:   Max: 6.2% Min: 2.3% Avg: 4.26%
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/Kconfig

@@ -17,7 +17,8 @@ if NET_VENDOR_AQUANTIA
 
 config AQTION
 	tristate "aQuantia AQtion(tm) Support"
-	depends on PCI && X86_64
+	depends on PCI
+	depends on X86_64 || ARM64 || COMPILE_TEST
 	---help---
 	  This enables the support for the aQuantia AQtion(tm) Ethernet card.
 

drivers/net/ethernet/aquantia/atlantic/aq_cfg.h

@@ -16,7 +16,7 @@
 #define AQ_CFG_TCS_DEF    1U
 
 #define AQ_CFG_TXDS_DEF    4096U
-#define AQ_CFG_RXDS_DEF    1024U
+#define AQ_CFG_RXDS_DEF    2048U
 
 #define AQ_CFG_IS_POLLING_DEF 0U
 
@@ -34,10 +34,16 @@
 #define AQ_CFG_TCS_MAX    8U
 
 #define AQ_CFG_TX_FRAME_MAX  (16U * 1024U)
-#define AQ_CFG_RX_FRAME_MAX  (4U * 1024U)
+#define AQ_CFG_RX_FRAME_MAX  (2U * 1024U)
 
 #define AQ_CFG_TX_CLEAN_BUDGET 256U
 
+#define AQ_CFG_RX_REFILL_THRES 32U
+
+#define AQ_CFG_RX_HDR_SIZE 256U
+
+#define AQ_CFG_RX_PAGEORDER 0U
+
 /* LRO */
 #define AQ_CFG_IS_LRO_DEF           1U
 

drivers/net/ethernet/aquantia/atlantic/aq_nic.c

@@ -73,6 +73,7 @@ void aq_nic_cfg_start(struct aq_nic_s *self)
 	cfg->tx_itr = aq_itr_tx;
 	cfg->rx_itr = aq_itr_rx;
 
+	cfg->rxpageorder = AQ_CFG_RX_PAGEORDER;
 	cfg->is_rss = AQ_CFG_IS_RSS_DEF;
 	cfg->num_rss_queues = AQ_CFG_NUM_RSS_QUEUES_DEF;
 	cfg->aq_rss.base_cpu_number = AQ_CFG_RSS_BASE_CPU_NUM_DEF;

drivers/net/ethernet/aquantia/atlantic/aq_nic.h

@@ -31,6 +31,7 @@ struct aq_nic_cfg_s {
 	u32 itr;
 	u16 rx_itr;
 	u16 tx_itr;
+	u32 rxpageorder;
 	u32 num_rss_queues;
 	u32 mtu;
 	u32 flow_control;

drivers/net/ethernet/aquantia/atlantic/aq_ring.c

@@ -12,10 +12,89 @@
 #include "aq_ring.h"
 #include "aq_nic.h"
 #include "aq_hw.h"
+#include "aq_hw_utils.h"
 
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 
+static inline void aq_free_rxpage(struct aq_rxpage *rxpage, struct device *dev)
+{
+	unsigned int len = PAGE_SIZE << rxpage->order;
+
+	dma_unmap_page(dev, rxpage->daddr, len, DMA_FROM_DEVICE);
+
+	/* Drop the ref for being in the ring. */
+	__free_pages(rxpage->page, rxpage->order);
+	rxpage->page = NULL;
+}
+
+static int aq_get_rxpage(struct aq_rxpage *rxpage, unsigned int order,
+			 struct device *dev)
+{
+	struct page *page;
+	dma_addr_t daddr;
+	int ret = -ENOMEM;
+
+	page = dev_alloc_pages(order);
+	if (unlikely(!page))
+		goto err_exit;
+
+	daddr = dma_map_page(dev, page, 0, PAGE_SIZE << order,
+			     DMA_FROM_DEVICE);
+
+	if (unlikely(dma_mapping_error(dev, daddr)))
+		goto free_page;
+
+	rxpage->page = page;
+	rxpage->daddr = daddr;
+	rxpage->order = order;
+	rxpage->pg_off = 0;
+
+	return 0;
+
+free_page:
+	__free_pages(page, order);
+
+err_exit:
+	return ret;
+}
+
+static int aq_get_rxpages(struct aq_ring_s *self, struct aq_ring_buff_s *rxbuf,
+			  int order)
+{
+	int ret;
+
+	if (rxbuf->rxdata.page) {
+		/* One means ring is the only user and can reuse */
+		if (page_ref_count(rxbuf->rxdata.page) > 1) {
+			/* Try reuse buffer */
+			rxbuf->rxdata.pg_off += AQ_CFG_RX_FRAME_MAX;
+			if (rxbuf->rxdata.pg_off + AQ_CFG_RX_FRAME_MAX <=
+				(PAGE_SIZE << order)) {
+				self->stats.rx.pg_flips++;
+			} else {
+				/* Buffer exhausted. We have other users and
+				 * should release this page and realloc
+				 */
+				aq_free_rxpage(&rxbuf->rxdata,
+					       aq_nic_get_dev(self->aq_nic));
+				self->stats.rx.pg_losts++;
+			}
+		} else {
+			rxbuf->rxdata.pg_off = 0;
+			self->stats.rx.pg_reuses++;
+		}
+	}
+
+	if (!rxbuf->rxdata.page) {
+		ret = aq_get_rxpage(&rxbuf->rxdata, order,
+				    aq_nic_get_dev(self->aq_nic));
+		return ret;
+	}
+
+	return 0;
+}
+
 static struct aq_ring_s *aq_ring_alloc(struct aq_ring_s *self,
 				       struct aq_nic_s *aq_nic)
 {
@@ -81,6 +160,11 @@ struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
 	self->idx = idx;
 	self->size = aq_nic_cfg->rxds;
 	self->dx_size = aq_nic_cfg->aq_hw_caps->rxd_size;
+	self->page_order = fls(AQ_CFG_RX_FRAME_MAX / PAGE_SIZE +
+			       (AQ_CFG_RX_FRAME_MAX % PAGE_SIZE ? 1 : 0)) - 1;
+
+	if (aq_nic_cfg->rxpageorder > self->page_order)
+		self->page_order = aq_nic_cfg->rxpageorder;
 
 	self = aq_ring_alloc(self, aq_nic);
 	if (!self) {
@@ -201,22 +285,21 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 		     int budget)
 {
 	struct net_device *ndev = aq_nic_get_ndev(self->aq_nic);
-	int err = 0;
 	bool is_rsc_completed = true;
+	int err = 0;
 
 	for (; (self->sw_head != self->hw_head) && budget;
 		self->sw_head = aq_ring_next_dx(self, self->sw_head),
 		--budget, ++(*work_done)) {
 		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
+		struct aq_ring_buff_s *buff_ = NULL;
 		struct sk_buff *skb = NULL;
 		unsigned int next_ = 0U;
 		unsigned int i = 0U;
-		struct aq_ring_buff_s *buff_ = NULL;
+		u16 hdr_len;
 
-		if (buff->is_error) {
-			__free_pages(buff->page, 0);
+		if (buff->is_error)
 			continue;
-		}
 
 		if (buff->is_cleaned)
 			continue;
@@ -246,45 +329,66 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 			}
 		}
 
+		dma_sync_single_range_for_cpu(aq_nic_get_dev(self->aq_nic),
+					      buff->rxdata.daddr,
+					      buff->rxdata.pg_off,
+					      buff->len, DMA_FROM_DEVICE);
+
 		/* for single fragment packets use build_skb() */
 		if (buff->is_eop &&
 		    buff->len <= AQ_CFG_RX_FRAME_MAX - AQ_SKB_ALIGN) {
-			skb = build_skb(page_address(buff->page),
+			skb = build_skb(aq_buf_vaddr(&buff->rxdata),
 					AQ_CFG_RX_FRAME_MAX);
 			if (unlikely(!skb)) {
 				err = -ENOMEM;
 				goto err_exit;
 			}
-
 			skb_put(skb, buff->len);
+			page_ref_inc(buff->rxdata.page);
 		} else {
-			skb = netdev_alloc_skb(ndev, ETH_HLEN);
+			skb = napi_alloc_skb(napi, AQ_CFG_RX_HDR_SIZE);
 			if (unlikely(!skb)) {
 				err = -ENOMEM;
 				goto err_exit;
 			}
-			skb_put(skb, ETH_HLEN);
-			memcpy(skb->data, page_address(buff->page), ETH_HLEN);
 
-			skb_add_rx_frag(skb, 0, buff->page, ETH_HLEN,
-					buff->len - ETH_HLEN,
-					SKB_TRUESIZE(buff->len - ETH_HLEN));
+			hdr_len = buff->len;
+			if (hdr_len > AQ_CFG_RX_HDR_SIZE)
+				hdr_len = eth_get_headlen(aq_buf_vaddr(&buff->rxdata),
+							  AQ_CFG_RX_HDR_SIZE);
+
+			memcpy(__skb_put(skb, hdr_len), aq_buf_vaddr(&buff->rxdata),
+			       ALIGN(hdr_len, sizeof(long)));
+
+			if (buff->len - hdr_len > 0) {
+				skb_add_rx_frag(skb, 0, buff->rxdata.page,
+						buff->rxdata.pg_off + hdr_len,
+						buff->len - hdr_len,
+						AQ_CFG_RX_FRAME_MAX);
+				page_ref_inc(buff->rxdata.page);
+			}
 
 			if (!buff->is_eop) {
-				for (i = 1U, next_ = buff->next,
-				     buff_ = &self->buff_ring[next_];
-				     true; next_ = buff_->next,
-				     buff_ = &self->buff_ring[next_], ++i) {
-					skb_add_rx_frag(skb, i,
-							buff_->page, 0,
+				buff_ = buff;
+				i = 1U;
+				do {
+					next_ = buff_->next,
+					buff_ = &self->buff_ring[next_];
+
+					dma_sync_single_range_for_cpu(
+							aq_nic_get_dev(self->aq_nic),
+							buff_->rxdata.daddr,
+							buff_->rxdata.pg_off,
 							buff_->len,
-							SKB_TRUESIZE(buff->len -
-							ETH_HLEN));
+							DMA_FROM_DEVICE);
+					skb_add_rx_frag(skb, i++,
+							buff_->rxdata.page,
+							buff_->rxdata.pg_off,
+							buff_->len,
+							AQ_CFG_RX_FRAME_MAX);
+					page_ref_inc(buff_->rxdata.page);
 					buff_->is_cleaned = 1;
-
-					if (buff_->is_eop)
-						break;
-				}
+				} while (!buff_->is_eop);
 			}
 		}
 
@@ -310,43 +414,31 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
 
 int aq_ring_rx_fill(struct aq_ring_s *self)
 {
-	unsigned int pages_order = fls(AQ_CFG_RX_FRAME_MAX / PAGE_SIZE +
-		(AQ_CFG_RX_FRAME_MAX % PAGE_SIZE ? 1 : 0)) - 1;
+	unsigned int page_order = self->page_order;
 	struct aq_ring_buff_s *buff = NULL;
 	int err = 0;
 	int i = 0;
 
+	if (aq_ring_avail_dx(self) < min_t(unsigned int, AQ_CFG_RX_REFILL_THRES,
+					   self->size / 2))
+		return err;
+
 	for (i = aq_ring_avail_dx(self); i--;
 		self->sw_tail = aq_ring_next_dx(self, self->sw_tail)) {
 		buff = &self->buff_ring[self->sw_tail];
 
 		buff->flags = 0U;
 		buff->len = AQ_CFG_RX_FRAME_MAX;
 
-		buff->page = alloc_pages(GFP_ATOMIC | __GFP_COMP, pages_order);
-		if (!buff->page) {
-			err = -ENOMEM;
+		err = aq_get_rxpages(self, buff, page_order);
+		if (err)
 			goto err_exit;
-		}
-
-		buff->pa = dma_map_page(aq_nic_get_dev(self->aq_nic),
-					buff->page, 0,
-					AQ_CFG_RX_FRAME_MAX, DMA_FROM_DEVICE);
-
-		if (dma_mapping_error(aq_nic_get_dev(self->aq_nic), buff->pa)) {
-			err = -ENOMEM;
-			goto err_exit;
-		}
 
+		buff->pa = aq_buf_daddr(&buff->rxdata);
 		buff = NULL;
 	}
 
 err_exit:
-	if (err < 0) {
-		if (buff && buff->page)
-			__free_pages(buff->page, 0);
-	}
-
 	return err;
 }
 
@@ -359,10 +451,7 @@ void aq_ring_rx_deinit(struct aq_ring_s *self)
 		self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
 		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
 
-		dma_unmap_page(aq_nic_get_dev(self->aq_nic), buff->pa,
-			       AQ_CFG_RX_FRAME_MAX, DMA_FROM_DEVICE);
-
-		__free_pages(buff->page, 0);
+		aq_free_rxpage(&buff->rxdata, aq_nic_get_dev(self->aq_nic));
 	}
 
 err_exit:;