net: hns: Add self-adaptive interrupt coalesce support in hns driver

When deal with low and high throughput, it is hard to achiece both
high performance and low latency. In order to achiece that, this patch
calculates the rx rate, and adjust the interrupt coalesce parameter
accordingly.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Tested-by: Weiwei Deng <dengweiwei@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 126 insertions, 8 deletions

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index 3987699f8fe6..832f27792e3f 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -812,6 +812,112 @@ static int hns_desc_unused(struct hnae_ring *ring)
 	return ((ntc >= ntu) ? 0 : ring->desc_num) + ntc - ntu;
 }
 
+#define HNS_LOWEST_LATENCY_RATE		27	/* 27 MB/s */
+#define HNS_LOW_LATENCY_RATE			80	/* 80 MB/s */
+
+#define HNS_COAL_BDNUM			3
+
+static u32 hns_coal_rx_bdnum(struct hnae_ring *ring)
+{
+	bool coal_enable = ring->q->handle->coal_adapt_en;
+
+	if (coal_enable &&
+	    ring->coal_last_rx_bytes > HNS_LOWEST_LATENCY_RATE)
+		return HNS_COAL_BDNUM;
+	else
+		return 0;
+}
+
+static void hns_update_rx_rate(struct hnae_ring *ring)
+{
+	bool coal_enable = ring->q->handle->coal_adapt_en;
+	u32 time_passed_ms;
+	u64 total_bytes;
+
+	if (!coal_enable ||
+	    time_before(jiffies, ring->coal_last_jiffies + (HZ >> 4)))
+		return;
+
+	/* ring->stats.rx_bytes overflowed */
+	if (ring->coal_last_rx_bytes > ring->stats.rx_bytes) {
+		ring->coal_last_rx_bytes = ring->stats.rx_bytes;
+		ring->coal_last_jiffies = jiffies;
+		return;
+	}
+
+	total_bytes = ring->stats.rx_bytes - ring->coal_last_rx_bytes;
+	time_passed_ms = jiffies_to_msecs(jiffies - ring->coal_last_jiffies);
+	ring->coal_rx_rate = (total_bytes / time_passed_ms) >> 10;
+
+	ring->coal_last_rx_bytes = ring->stats.rx_bytes;
+	ring->coal_last_jiffies = jiffies;
+}
+
+/**
+ * smooth_alg - smoothing algrithm for adjusting coalesce parameter
+ **/
+static u32 smooth_alg(u32 new_param, u32 old_param)
+{
+	u32 gap = (new_param > old_param) ? new_param - old_param
+					  : old_param - new_param;
+
+	if (gap > 8)
+		gap >>= 3;
+
+	if (new_param > old_param)
+		return old_param + gap;
+	else
+		return old_param - gap;
+}
+
+/**
+ * hns_nic_adp_coalesce - self adapte coalesce according to rx rate
+ * @ring_data: pointer to hns_nic_ring_data
+ **/
+static void hns_nic_adpt_coalesce(struct hns_nic_ring_data *ring_data)
+{
+	struct hnae_ring *ring = ring_data->ring;
+	struct hnae_handle *handle = ring->q->handle;
+	u32 new_coal_param, old_coal_param = ring->coal_param;
+
+	if (ring->coal_rx_rate < HNS_LOWEST_LATENCY_RATE)
+		new_coal_param = HNAE_LOWEST_LATENCY_COAL_PARAM;
+	else if (ring->coal_rx_rate < HNS_LOW_LATENCY_RATE)
+		new_coal_param = HNAE_LOW_LATENCY_COAL_PARAM;
+	else
+		new_coal_param = HNAE_BULK_LATENCY_COAL_PARAM;
+
+	if (new_coal_param == old_coal_param &&
+	    new_coal_param == handle->coal_param)
+		return;
+
+	new_coal_param = smooth_alg(new_coal_param, old_coal_param);
+	ring->coal_param = new_coal_param;
+
+	/**
+	 * Because all ring in one port has one coalesce param, when one ring
+	 * calculate its own coalesce param, it cannot write to hardware at
+	 * once. There are three conditions as follows:
+	 *       1. current ring's coalesce param is larger than the hardware.
+	 *       2. or ring which adapt last time can change again.
+	 *       3. timeout.
+	 */
+	if (new_coal_param == handle->coal_param) {
+		handle->coal_last_jiffies = jiffies;
+		handle->coal_ring_idx = ring_data->queue_index;
+	} else if (new_coal_param > handle->coal_param ||
+		   handle->coal_ring_idx == ring_data->queue_index ||
+		   time_after(jiffies, handle->coal_last_jiffies + (HZ >> 4))) {
+		handle->dev->ops->set_coalesce_usecs(handle,
+					new_coal_param);
+		handle->dev->ops->set_coalesce_frames(handle,
+					1, new_coal_param);
+		handle->coal_param = new_coal_param;
+		handle->coal_ring_idx = ring_data->queue_index;
+		handle->coal_last_jiffies = jiffies;
+	}
+}
+
 static int hns_nic_rx_poll_one(struct hns_nic_ring_data *ring_data,
 			       int budget, void *v)
 {
@@ -868,20 +974,27 @@ static bool hns_nic_rx_fini_pro(struct hns_nic_ring_data *ring_data)
 {
 	struct hnae_ring *ring = ring_data->ring;
 	int num = 0;
+	bool rx_stopped;
 
-	ring_data->ring->q->handle->dev->ops->toggle_ring_irq(ring, 0);
+	hns_update_rx_rate(ring);
 
 	/* for hardware bug fixed */
+	ring_data->ring->q->handle->dev->ops->toggle_ring_irq(ring, 0);
 	num = readl_relaxed(ring->io_base + RCB_REG_FBDNUM);
 
-	if (num > 0) {
+	if (num <= hns_coal_rx_bdnum(ring)) {
+		if (ring->q->handle->coal_adapt_en)
+			hns_nic_adpt_coalesce(ring_data);
+
+		rx_stopped = true;
+	} else {
 		ring_data->ring->q->handle->dev->ops->toggle_ring_irq(
 			ring_data->ring, 1);
 
-		return false;
-	} else {
-		return true;
+		rx_stopped = false;
 	}
+
+	return rx_stopped;
 }
 
 static bool hns_nic_rx_fini_pro_v2(struct hns_nic_ring_data *ring_data)
@@ -889,12 +1002,17 @@ static bool hns_nic_rx_fini_pro_v2(struct hns_nic_ring_data *ring_data)
 	struct hnae_ring *ring = ring_data->ring;
 	int num;
 
+	hns_update_rx_rate(ring);
 	num = readl_relaxed(ring->io_base + RCB_REG_FBDNUM);
 
-	if (!num)
+	if (num <= hns_coal_rx_bdnum(ring)) {
+		if (ring->q->handle->coal_adapt_en)
+			hns_nic_adpt_coalesce(ring_data);
+
 		return true;
-	else
-		return false;
+	}
+
+	return false;
 }
 
 static inline void hns_nic_reclaim_one_desc(struct hnae_ring *ring,