[dpdk-stable] [PATCH v4] net/i40e: fix incorrect byte counters

[Junyu Jiang]

This patch fixed the issue that rx/tx bytes statistics counters
overflowed on 48 bit limitation by enlarging the limitation.

Fixes: 4861cde46116 ("i40e: new poll mode driver")
Cc: stable at dpdk.org

Signed-off-by: Junyu Jiang <junyux.jiang at intel.com>
---
v4: put reading stats and extending in same function.
v3: create a function to hide the extension inside it.
v2: modify the error code
---
---
 doc/guides/nics/i40e.rst       |  7 ++++
 drivers/net/i40e/i40e_ethdev.c | 66 +++++++++++++++++++++-------------
 drivers/net/i40e/i40e_ethdev.h |  9 +++++
 3 files changed, 57 insertions(+), 25 deletions(-)

diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst
index b7430f6c4..4baa58be6 100644
--- a/doc/guides/nics/i40e.rst
+++ b/doc/guides/nics/i40e.rst
@@ -830,3 +830,10 @@ Tx bytes affected by the link status change
 
 For firmware versions prior to 6.01 for X710 series and 3.33 for X722 series, the tx_bytes statistics data is affected by
 the link down event. Each time the link status changes to down, the tx_bytes decreases 110 bytes.
+
+RX/TX statistics may be incorrect when register overflowed
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The rx_bytes/tx_bytes statistics register is 48 bit length. Although this limitation is enlarged to 64 bit length
+on the software side, but there is no way to detect if the overflow occurred more than once. So rx_bytes/tx_bytes
+statistics data is correct when statistics are updated at least once between two overflows.
diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
index 563f21d9d..6439baf2f 100644
--- a/drivers/net/i40e/i40e_ethdev.c
+++ b/drivers/net/i40e/i40e_ethdev.c
@@ -3052,6 +3052,21 @@ i40e_dev_link_update(struct rte_eth_dev *dev,
 	return ret;
 }
 
+static void
+i40e_stat_update_48_in_64(struct i40e_hw *hw, uint32_t hireg,
+			  uint32_t loreg, bool offset_loaded, uint64_t *offset,
+			  uint64_t *stat, uint64_t *prev_stat)
+{
+	i40e_stat_update_48(hw, hireg, loreg, offset_loaded, offset, stat);
+	/* enlarge the limitation when statistics counters overflowed */
+	if (offset_loaded) {
+		if (I40E_RXTX_BYTES_L_48_BIT(*prev_stat) > *stat)
+			*stat += (uint64_t)1 << I40E_48_BIT_WIDTH;
+		*stat += I40E_RXTX_BYTES_H_16_BIT(*prev_stat);
+	}
+	*prev_stat = *stat;
+}
+
 /* Get all the statistics of a VSI */
 void
 i40e_update_vsi_stats(struct i40e_vsi *vsi)
@@ -3061,9 +3076,9 @@ i40e_update_vsi_stats(struct i40e_vsi *vsi)
 	struct i40e_hw *hw = I40E_VSI_TO_HW(vsi);
 	int idx = rte_le_to_cpu_16(vsi->info.stat_counter_idx);
 
-	i40e_stat_update_48(hw, I40E_GLV_GORCH(idx), I40E_GLV_GORCL(idx),
-			    vsi->offset_loaded, &oes->rx_bytes,
-			    &nes->rx_bytes);
+	i40e_stat_update_48_in_64(hw, I40E_GLV_GORCH(idx), I40E_GLV_GORCL(idx),
+				  vsi->offset_loaded, &oes->rx_bytes,
+				  &nes->rx_bytes, &vsi->prev_rx_bytes);
 	i40e_stat_update_48(hw, I40E_GLV_UPRCH(idx), I40E_GLV_UPRCL(idx),
 			    vsi->offset_loaded, &oes->rx_unicast,
 			    &nes->rx_unicast);
@@ -3084,9 +3099,9 @@ i40e_update_vsi_stats(struct i40e_vsi *vsi)
 	i40e_stat_update_32(hw, I40E_GLV_RUPP(idx), vsi->offset_loaded,
 			    &oes->rx_unknown_protocol,
 			    &nes->rx_unknown_protocol);
-	i40e_stat_update_48(hw, I40E_GLV_GOTCH(idx), I40E_GLV_GOTCL(idx),
-			    vsi->offset_loaded, &oes->tx_bytes,
-			    &nes->tx_bytes);
+	i40e_stat_update_48_in_64(hw, I40E_GLV_GOTCH(idx), I40E_GLV_GOTCL(idx),
+				  vsi->offset_loaded, &oes->tx_bytes,
+				  &nes->tx_bytes, &vsi->prev_tx_bytes);
 	i40e_stat_update_48(hw, I40E_GLV_UPTCH(idx), I40E_GLV_UPTCL(idx),
 			    vsi->offset_loaded, &oes->tx_unicast,
 			    &nes->tx_unicast);
@@ -3128,17 +3143,18 @@ i40e_read_stats_registers(struct i40e_pf *pf, struct i40e_hw *hw)
 	struct i40e_hw_port_stats *os = &pf->stats_offset; /* old stats */
 
 	/* Get rx/tx bytes of internal transfer packets */
-	i40e_stat_update_48(hw, I40E_GLV_GORCH(hw->port),
-			I40E_GLV_GORCL(hw->port),
-			pf->offset_loaded,
-			&pf->internal_stats_offset.rx_bytes,
-			&pf->internal_stats.rx_bytes);
-
-	i40e_stat_update_48(hw, I40E_GLV_GOTCH(hw->port),
-			I40E_GLV_GOTCL(hw->port),
-			pf->offset_loaded,
-			&pf->internal_stats_offset.tx_bytes,
-			&pf->internal_stats.tx_bytes);
+	i40e_stat_update_48_in_64(hw, I40E_GLV_GORCH(hw->port),
+				  I40E_GLV_GORCL(hw->port),
+				  pf->offset_loaded,
+				  &pf->internal_stats_offset.rx_bytes,
+				  &pf->internal_stats.rx_bytes,
+				  &pf->internal_prev_rx_bytes);
+	i40e_stat_update_48_in_64(hw, I40E_GLV_GOTCH(hw->port),
+				  I40E_GLV_GOTCL(hw->port),
+				  pf->offset_loaded,
+				  &pf->internal_stats_offset.tx_bytes,
+				  &pf->internal_stats.tx_bytes,
+				  &pf->internal_prev_tx_bytes);
 	/* Get total internal rx packet count */
 	i40e_stat_update_48(hw, I40E_GLV_UPRCH(hw->port),
 			    I40E_GLV_UPRCL(hw->port),
@@ -3178,10 +3194,10 @@ i40e_read_stats_registers(struct i40e_pf *pf, struct i40e_hw *hw)
 		pf->internal_stats.rx_broadcast) * RTE_ETHER_CRC_LEN;
 
 	/* Get statistics of struct i40e_eth_stats */
-	i40e_stat_update_48(hw, I40E_GLPRT_GORCH(hw->port),
-			    I40E_GLPRT_GORCL(hw->port),
-			    pf->offset_loaded, &os->eth.rx_bytes,
-			    &ns->eth.rx_bytes);
+	i40e_stat_update_48_in_64(hw, I40E_GLPRT_GORCH(hw->port),
+				  I40E_GLPRT_GORCL(hw->port),
+				  pf->offset_loaded, &os->eth.rx_bytes,
+				  &ns->eth.rx_bytes, &pf->prev_rx_bytes);
 	i40e_stat_update_48(hw, I40E_GLPRT_UPRCH(hw->port),
 			    I40E_GLPRT_UPRCL(hw->port),
 			    pf->offset_loaded, &os->eth.rx_unicast,
@@ -3236,10 +3252,10 @@ i40e_read_stats_registers(struct i40e_pf *pf, struct i40e_hw *hw)
 			    pf->offset_loaded,
 			    &os->eth.rx_unknown_protocol,
 			    &ns->eth.rx_unknown_protocol);
-	i40e_stat_update_48(hw, I40E_GLPRT_GOTCH(hw->port),
-			    I40E_GLPRT_GOTCL(hw->port),
-			    pf->offset_loaded, &os->eth.tx_bytes,
-			    &ns->eth.tx_bytes);
+	i40e_stat_update_48_in_64(hw, I40E_GLPRT_GOTCH(hw->port),
+				  I40E_GLPRT_GOTCL(hw->port),
+				  pf->offset_loaded, &os->eth.tx_bytes,
+				  &ns->eth.tx_bytes, &pf->prev_tx_bytes);
 	i40e_stat_update_48(hw, I40E_GLPRT_UPTCH(hw->port),
 			    I40E_GLPRT_UPTCL(hw->port),
 			    pf->offset_loaded, &os->eth.tx_unicast,
diff --git a/drivers/net/i40e/i40e_ethdev.h b/drivers/net/i40e/i40e_ethdev.h
index 19f821829..1466998aa 100644
--- a/drivers/net/i40e/i40e_ethdev.h
+++ b/drivers/net/i40e/i40e_ethdev.h
@@ -282,6 +282,9 @@ struct rte_flow {
 #define I40E_ETH_OVERHEAD \
 	(RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE * 2)
 
+#define I40E_RXTX_BYTES_H_16_BIT(bytes) ((bytes) & ~I40E_48_BIT_MASK)
+#define I40E_RXTX_BYTES_L_48_BIT(bytes) ((bytes) & I40E_48_BIT_MASK)
+
 struct i40e_adapter;
 struct rte_pci_driver;
 
@@ -399,6 +402,8 @@ struct i40e_vsi {
 	uint8_t vlan_anti_spoof_on; /* The VLAN anti-spoofing enabled */
 	uint8_t vlan_filter_on; /* The VLAN filter enabled */
 	struct i40e_bw_info bw_info; /* VSI bandwidth information */
+	uint64_t prev_rx_bytes;
+	uint64_t prev_tx_bytes;
 };
 
 struct pool_entry {
@@ -1156,6 +1161,10 @@ struct i40e_pf {
 	uint16_t switch_domain_id;
 
 	struct i40e_vf_msg_cfg vf_msg_cfg;
+	uint64_t prev_rx_bytes;
+	uint64_t prev_tx_bytes;
+	uint64_t internal_prev_rx_bytes;
+	uint64_t internal_prev_tx_bytes;
 };
 
 enum pending_msg {
-- 
2.17.1