e1000/e1000e: implement a simple interrupt moderation
Back before e1000-7.3.20, the e1000 driver had a simple algorithm that
managed interrupt moderation. The driver was updated in 7.3.20 to
have the new "adaptive" interrupt moderation but we have customer
requests to redeploy the old way as an option. This patch adds the
old functionality back. The new functionality can be enabled via
module parameter or at runtime via ethtool.
Module parameter: (InterruptThrottleRate=4) to use this new
moderation method.
Ethtool method: ethtool -C ethX rx-usecs 4
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@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/e1000e/ethtool.c b/drivers/net/e1000e/ethtool.c
index b72c1c0..6ff376c 100644
--- a/drivers/net/e1000e/ethtool.c
+++ b/drivers/net/e1000e/ethtool.c
@@ -1890,7 +1890,7 @@
{
struct e1000_adapter *adapter = netdev_priv(netdev);
- if (adapter->itr_setting <= 3)
+ if (adapter->itr_setting <= 4)
ec->rx_coalesce_usecs = adapter->itr_setting;
else
ec->rx_coalesce_usecs = 1000000 / adapter->itr_setting;
@@ -1905,12 +1905,14 @@
struct e1000_hw *hw = &adapter->hw;
if ((ec->rx_coalesce_usecs > E1000_MAX_ITR_USECS) ||
- ((ec->rx_coalesce_usecs > 3) &&
+ ((ec->rx_coalesce_usecs > 4) &&
(ec->rx_coalesce_usecs < E1000_MIN_ITR_USECS)) ||
(ec->rx_coalesce_usecs == 2))
return -EINVAL;
- if (ec->rx_coalesce_usecs <= 3) {
+ if (ec->rx_coalesce_usecs == 4) {
+ adapter->itr = adapter->itr_setting = 4;
+ } else if (ec->rx_coalesce_usecs <= 3) {
adapter->itr = 20000;
adapter->itr_setting = ec->rx_coalesce_usecs;
} else {