ixgbe: Introduce adaptive interrupt moderation

82598 can produce a formidable interrupt rate, and is largely
unusable without some form of moderation. The default behaviour
before this patch is to limit irq's to a reasonable number.
However, just like our other drivers we can reduce latency
for small packet-type traffic considerably by allowing the
irq rate to go up dynamically.

This patch introduces a simple irq moderation algorithm based
on traffic analysis. The driver will use more CPU to service
small packets quicker but will perform the same on bulk traffic
as the old code.

Signed-off-by: Ayyappan Veeraiyan <ayyappan.veeraiyan@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h
index 20774772b608..79f5519e2aa9 100644
--- a/drivers/net/ixgbe/ixgbe.h
+++ b/drivers/net/ixgbe/ixgbe.h
@@ -136,6 +136,8 @@ struct ixgbe_ring {
 	u16 head;
 	u16 tail;
 
+	unsigned int total_bytes;
+	unsigned int total_packets;
 
 	u16 reg_idx; /* holds the special value that gets the hardware register
 		      * offset associated with this ring, which is different
@@ -174,6 +176,8 @@ struct ixgbe_q_vector {
 	DECLARE_BITMAP(txr_idx, MAX_TX_QUEUES); /* Tx ring indices */
 	u8 rxr_count;     /* Rx ring count assigned to this vector */
 	u8 txr_count;     /* Tx ring count assigned to this vector */
+	u8 tx_eitr;
+	u8 rx_eitr;
 	u32 eitr;
 };
 
@@ -215,6 +219,11 @@ struct ixgbe_adapter {
 	struct ixgbe_q_vector q_vector[MAX_MSIX_Q_VECTORS];
 	char name[MAX_MSIX_COUNT][IFNAMSIZ + 5];
 
+	/* Interrupt Throttle Rate */
+	u32 itr_setting;
+	u16 eitr_low;
+	u16 eitr_high;
+
 	/* TX */
 	struct ixgbe_ring *tx_ring;	/* One per active queue */
 	u64 restart_queue;