i40e/i40evf: adjust interrupt throttle less frequently
The adaptive ITR (interrupt throttle rate) algorithm was adjusting
the hardware's interrupt rate too frequently. This caused a lot
of variation in the interrupt rate for fairly constant workloads.
Change the code to have a counter and adjust only once every N
number of interrupts.
Change-ID: I0460f1f86571037484eca5aca36ac4d889cb8389
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/i40evf/i40evf.h b/drivers/net/ethernet/intel/i40evf/i40evf.h
index 22841c6..22fc3d4 100644
--- a/drivers/net/ethernet/intel/i40evf/i40evf.h
+++ b/drivers/net/ethernet/intel/i40evf/i40evf.h
@@ -112,6 +112,8 @@
struct i40e_ring_container tx;
u32 ring_mask;
u8 num_ringpairs; /* total number of ring pairs in vector */
+#define ITR_COUNTDOWN_START 100
+ u8 itr_countdown; /* when 0 or 1 update ITR */
int v_idx; /* vector index in list */
char name[IFNAMSIZ + 9];
bool arm_wb_state;