igb: cap interrupts at 20K per queue when in itr mode 3
In order to maintain similar performance between MSI-X and
legacy/MSI interrupts, this patch reduces the number of interrupts
when receiving small packets to 20K when in interrupt throttle
rate mode 3.
Signed-off-by: Nicholas Nunley <nicholasx.d.nunley@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index eb48e1a..4ccc7fc 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -3260,6 +3260,10 @@
else
new_val = avg_wire_size / 2;
+ /* when in itr mode 3 do not exceed 20K ints/sec */
+ if (adapter->rx_itr_setting == 3 && new_val < 196)
+ new_val = 196;
+
set_itr_val:
if (new_val != q_vector->itr_val) {
q_vector->itr_val = new_val;