igbvf: refactor Interrupt Throttle Rate code

The existing ITR code is broken and confusing, with lots of similarly-named
variables that do different things. Additionally, after the driver carefully
determines the optimal interrupt rate for the adapter, it then
ignores it and always writes a fixed, suboptimal value.

This patch refactors that code to make variable names more descriptive of
what they actually do, and then actually writes the calculated result to
the hardware.

Preliminary testing shows that netperf TCP_STREAM tests goes from ~918Mbps
to ~940Mbps, and TCP_RR goes from ~2k transactions/sec up to > 8k.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Robert E Garrett <robertX.e.garrett@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 15 insertions, 12 deletions

diff --git a/drivers/net/ethernet/intel/igbvf/igbvf.h b/drivers/net/ethernet/intel/igbvf/igbvf.h
index 2c6d87e..a895e2f 100644
--- a/drivers/net/ethernet/intel/igbvf/igbvf.h
+++ b/drivers/net/ethernet/intel/igbvf/igbvf.h
@@ -43,7 +43,18 @@ struct igbvf_info;
 struct igbvf_adapter;
 
 /* Interrupt defines */
-#define IGBVF_START_ITR                 648 /* ~6000 ints/sec */
+#define IGBVF_START_ITR                    488 /* ~8000 ints/sec */
+#define IGBVF_4K_ITR                       980
+#define IGBVF_20K_ITR                      196
+#define IGBVF_70K_ITR                       56
+
+enum latency_range {
+	lowest_latency = 0,
+	low_latency = 1,
+	bulk_latency = 2,
+	latency_invalid = 255
+};
+
 
 /* Interrupt modes, as used by the IntMode parameter */
 #define IGBVF_INT_MODE_LEGACY           0
@@ -155,6 +166,7 @@ struct igbvf_ring {
 	char name[IFNAMSIZ + 5];
 	u32 eims_value;
 	u32 itr_val;
+	enum latency_range itr_range;
 	u16 itr_register;
 	int set_itr;
 
@@ -187,10 +199,8 @@ struct igbvf_adapter {
 	unsigned long state;
 
 	/* Interrupt Throttle Rate */
-	u32 itr;
-	u32 itr_setting;
-	u16 tx_itr;
-	u16 rx_itr;
+	u32 requested_itr; /* ints/sec or adaptive */
+	u32 current_itr; /* Actual ITR register value, not ints/sec */
 
 	/*
 	 * Tx
@@ -299,13 +309,6 @@ enum igbvf_state_t {
 	__IGBVF_DOWN
 };
 
-enum latency_range {
-	lowest_latency = 0,
-	low_latency = 1,
-	bulk_latency = 2,
-	latency_invalid = 255
-};
-
 extern char igbvf_driver_name[];
 extern const char igbvf_driver_version[];