From: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
There were a couple cases where the ITR value generated via the adaptive
ITR scheme could exceed 126. This resulted in the value becoming either 0
or something less than 10. Switching back and forth between a value less
than 10 and a value greater than 10 can cause issues as certain hardware
features such as RSC to not function well when the ITR value has dropped
that low.
CC: stable@xxxxxxxxxxxxxxx
Fixes: b4ded8327fea ("ixgbe: Update adaptive ITR algorithm")
Reported-by: Gregg Leventhal <gleventhal@xxxxxxxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Tested-by: Andrew Bowers <andrewx.bowers@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
---
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 7882148abb43..77ca9005dc41 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2621,7 +2621,7 @@ static void ixgbe_update_itr(struct ixgbe_q_vector *q_vector,
/* 16K ints/sec to 9.2K ints/sec */
avg_wire_size *= 15;
avg_wire_size += 11452;
- } else if (avg_wire_size <= 1980) {
+ } else if (avg_wire_size < 1968) {
/* 9.2K ints/sec to 8K ints/sec */
avg_wire_size *= 5;
avg_wire_size += 22420;
@@ -2654,6 +2654,8 @@ static void ixgbe_update_itr(struct ixgbe_q_vector *q_vector,
case IXGBE_LINK_SPEED_2_5GB_FULL:
case IXGBE_LINK_SPEED_1GB_FULL:
case IXGBE_LINK_SPEED_10_FULL:
+ if (avg_wire_size > 8064)
+ avg_wire_size = 8064;
itr += DIV_ROUND_UP(avg_wire_size,
IXGBE_ITR_ADAPTIVE_MIN_INC * 64) *
IXGBE_ITR_ADAPTIVE_MIN_INC;
--
2.21.0
