[dpdk-dev] [PATCH v3] net/i40e: add alarm handler

[Beilei Xing]

This patch adds alarm handler, and then i40e
PF will use alarm handler instead of interrupt
handler when device is started and Rx interrupt
mode is disabled. This way will save CPU cycles
during receiving packets.

Signed-off-by: Beilei Xing <beilei.xing at intel.com>
---
 drivers/net/i40e/i40e_ethdev.c | 67 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 65 insertions(+), 2 deletions(-)

v3 changes:
 - Replace interrupt handler with alarm handler when device is started.
v2 changes:
 - Remove PF interrupt handler only when multi-driver is enabled.

diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
index 85a6a86..31b5a49 100644
--- a/drivers/net/i40e/i40e_ethdev.c
+++ b/drivers/net/i40e/i40e_ethdev.c
@@ -292,6 +292,7 @@ static void i40e_stat_update_48(struct i40e_hw *hw,
 			       uint64_t *stat);
 static void i40e_pf_config_irq0(struct i40e_hw *hw, bool no_queue);
 static void i40e_dev_interrupt_handler(void *param);
+static void i40e_dev_alarm_handler(void *param);
 static int i40e_res_pool_init(struct i40e_res_pool_info *pool,
 				uint32_t base, uint32_t num);
 static void i40e_res_pool_destroy(struct i40e_res_pool_info *pool);
@@ -1201,6 +1202,8 @@ i40e_aq_debug_write_global_register(struct i40e_hw *hw,
 	return i40e_aq_debug_write_register(hw, reg_addr, reg_val, cmd_details);
 }
 
+#define I40E_ALARM_INTERVAL 50000 /* us */
+
 static int
 eth_i40e_dev_init(struct rte_eth_dev *dev, void *init_params __rte_unused)
 {
@@ -2293,8 +2296,13 @@ i40e_dev_start(struct rte_eth_dev *dev)
 		i40e_dev_link_update(dev, 0);
 	}
 
-	/* enable uio intr after callback register */
-	rte_intr_enable(intr_handle);
+	if (dev->data->dev_conf.intr_conf.rxq == 0) {
+		rte_eal_alarm_set(I40E_ALARM_INTERVAL,
+				  i40e_dev_alarm_handler, dev);
+	} else {
+		/* enable uio intr after callback register */
+		rte_intr_enable(intr_handle);
+	}
 
 	i40e_filter_restore(pf);
 
@@ -2324,6 +2332,12 @@ i40e_dev_stop(struct rte_eth_dev *dev)
 
 	if (hw->adapter_stopped == 1)
 		return;
+
+	if (dev->data->dev_conf.intr_conf.rxq == 0) {
+		rte_eal_alarm_cancel(i40e_dev_alarm_handler, dev);
+		rte_intr_enable(intr_handle);
+	}
+
 	/* Disable all queues */
 	i40e_dev_switch_queues(pf, FALSE);
 
@@ -6552,6 +6566,55 @@ i40e_dev_interrupt_handler(void *param)
 	rte_intr_enable(dev->intr_handle);
 }
 
+static void
+i40e_dev_alarm_handler(void *param)
+{
+	struct rte_eth_dev *dev = (struct rte_eth_dev *)param;
+	struct i40e_hw *hw = I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
+	uint32_t icr0;
+
+	/* Disable interrupt */
+	i40e_pf_disable_irq0(hw);
+
+	/* read out interrupt causes */
+	icr0 = I40E_READ_REG(hw, I40E_PFINT_ICR0);
+
+	/* No interrupt event indicated */
+	if (!(icr0 & I40E_PFINT_ICR0_INTEVENT_MASK)) {
+		PMD_DRV_LOG(INFO, "No interrupt event");
+		goto done;
+	}
+	if (icr0 & I40E_PFINT_ICR0_ECC_ERR_MASK)
+		PMD_DRV_LOG(ERR, "ICR0: unrecoverable ECC error");
+	if (icr0 & I40E_PFINT_ICR0_MAL_DETECT_MASK)
+		PMD_DRV_LOG(ERR, "ICR0: malicious programming detected");
+	if (icr0 & I40E_PFINT_ICR0_GRST_MASK)
+		PMD_DRV_LOG(INFO, "ICR0: global reset requested");
+	if (icr0 & I40E_PFINT_ICR0_PCI_EXCEPTION_MASK)
+		PMD_DRV_LOG(INFO, "ICR0: PCI exception activated");
+	if (icr0 & I40E_PFINT_ICR0_STORM_DETECT_MASK)
+		PMD_DRV_LOG(INFO, "ICR0: a change in the storm control state");
+	if (icr0 & I40E_PFINT_ICR0_HMC_ERR_MASK)
+		PMD_DRV_LOG(ERR, "ICR0: HMC error");
+	if (icr0 & I40E_PFINT_ICR0_PE_CRITERR_MASK)
+		PMD_DRV_LOG(ERR, "ICR0: protocol engine critical error");
+
+	if (icr0 & I40E_PFINT_ICR0_VFLR_MASK) {
+		PMD_DRV_LOG(INFO, "ICR0: VF reset detected");
+		i40e_dev_handle_vfr_event(dev);
+	}
+	if (icr0 & I40E_PFINT_ICR0_ADMINQ_MASK) {
+		PMD_DRV_LOG(INFO, "ICR0: adminq event");
+		i40e_dev_handle_aq_msg(dev);
+	}
+
+done:
+	/* Enable interrupt */
+	i40e_pf_enable_irq0(hw);
+	rte_eal_alarm_set(I40E_ALARM_INTERVAL,
+			  i40e_dev_alarm_handler, dev);
+}
+
 int
 i40e_add_macvlan_filters(struct i40e_vsi *vsi,
 			 struct i40e_macvlan_filter *filter,
-- 
2.5.5