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ixgbe: Disable RSC when ITR setting is too high to allow RSC

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RSC will flush its descriptors every time the interrupt throttle timer
expires.  In addition there are known issues with RSC when the rx-usecs
value is set too low.  As such we are forced to clear the RSC_ENABLED bit
and reset the adapter when the rx-usecs value is set too low.

However we do not need to clear the NETIF_F_LRO flag because it is used to
indicate that the user wants to leave the LRO feature enabled, and in fact
with this change we will now re-enable RSC as soon as the rx-usecs value is
increased and the flag is still set.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Alexander Duyck 2010-11-16 19:26:57 -08:00 committed by Jeff Kirsher
parent 73c4b7cdd2
commit 80fba3f434
1 changed files with 53 additions and 37 deletions
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90
drivers/net/ixgbe/ixgbe_ethtool.c
View file

@ -1975,6 +1975,41 @@ static int ixgbe_get_coalesce(struct net_device *netdev,
return 0;
}
/*
* this function must be called before setting the new value of
* rx_itr_setting
*/
static bool ixgbe_update_rsc(struct ixgbe_adapter *adapter,
struct ethtool_coalesce *ec)
{
struct net_device *netdev = adapter->netdev;
if (!(adapter->flags2 & IXGBE_FLAG2_RSC_CAPABLE))
return false;
/* if interrupt rate is too high then disable RSC */
if (ec->rx_coalesce_usecs != 1 &&
ec->rx_coalesce_usecs <= 1000000/IXGBE_MAX_RSC_INT_RATE) {
if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) {
e_info(probe, "rx-usecs set too low, "
"disabling RSC\n");
adapter->flags2 &= ~IXGBE_FLAG2_RSC_ENABLED;
return true;
}
} else {
/* check the feature flag value and enable RSC if necessary */
if ((netdev->features & NETIF_F_LRO) &&
!(adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED)) {
e_info(probe, "rx-usecs set to %d, "
"re-enabling RSC\n",
ec->rx_coalesce_usecs);
adapter->flags2 |= IXGBE_FLAG2_RSC_ENABLED;
return true;
}
}
return false;
}
static int ixgbe_set_coalesce(struct net_device *netdev,
struct ethtool_coalesce *ec)
{
@ -1992,17 +2027,14 @@ static int ixgbe_set_coalesce(struct net_device *netdev,
adapter->tx_ring[0]->work_limit = ec->tx_max_coalesced_frames_irq;
if (ec->rx_coalesce_usecs > 1) {
u32 max_int;
if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED)
max_int = IXGBE_MAX_RSC_INT_RATE;
else
max_int = IXGBE_MAX_INT_RATE;
/* check the limits */
if ((1000000/ec->rx_coalesce_usecs > max_int) ||
if ((1000000/ec->rx_coalesce_usecs > IXGBE_MAX_INT_RATE) ||
(1000000/ec->rx_coalesce_usecs < IXGBE_MIN_INT_RATE))
return -EINVAL;
/* check the old value and enable RSC if necessary */
need_reset = ixgbe_update_rsc(adapter, ec);
/* store the value in ints/second */
adapter->rx_eitr_param = 1000000/ec->rx_coalesce_usecs;
@ -2011,32 +2043,21 @@ static int ixgbe_set_coalesce(struct net_device *netdev,
/* clear the lower bit as its used for dynamic state */
adapter->rx_itr_setting &= ~1;
} else if (ec->rx_coalesce_usecs == 1) {
/* check the old value and enable RSC if necessary */
need_reset = ixgbe_update_rsc(adapter, ec);
/* 1 means dynamic mode */
adapter->rx_eitr_param = 20000;
adapter->rx_itr_setting = 1;
} else {
/* check the old value and enable RSC if necessary */
need_reset = ixgbe_update_rsc(adapter, ec);
/*
* any other value means disable eitr, which is best
* served by setting the interrupt rate very high
*/
adapter->rx_eitr_param = IXGBE_MAX_INT_RATE;
adapter->rx_itr_setting = 0;
/*
* if hardware RSC is enabled, disable it when
* setting low latency mode, to avoid errata, assuming
* that when the user set low latency mode they want
* it at the cost of anything else
*/
if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) {
adapter->flags2 &= ~IXGBE_FLAG2_RSC_ENABLED;
if (netdev->features & NETIF_F_LRO) {
netdev->features &= ~NETIF_F_LRO;
e_info(probe, "rx-usecs set to 0, "
"disabling RSC\n");
}
need_reset = true;
}
}
if (ec->tx_coalesce_usecs > 1) {
@ -2123,15 +2144,15 @@ static int ixgbe_set_flags(struct net_device *netdev, u32 data)
return rc;
/* if state changes we need to update adapter->flags and reset */
if (adapter->flags2 & IXGBE_FLAG2_RSC_CAPABLE) {
/*
* cast both to bool and verify if they are set the same
* but only enable RSC if itr is non-zero, as
* itr=0 and RSC are mutually exclusive
*/
if (((!!(data & ETH_FLAG_LRO)) !=
(!!(adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED))) &&
adapter->rx_itr_setting) {
if ((adapter->flags2 & IXGBE_FLAG2_RSC_CAPABLE) &&
(!!(data & ETH_FLAG_LRO) !=
!!(adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED))) {
if ((data & ETH_FLAG_LRO) &&
(!adapter->rx_itr_setting ||
(adapter->rx_itr_setting > IXGBE_MAX_RSC_INT_RATE))) {
e_info(probe, "rx-usecs set too low, "
"not enabling RSC.\n");
} else {
adapter->flags2 ^= IXGBE_FLAG2_RSC_ENABLED;
switch (adapter->hw.mac.type) {
case ixgbe_mac_82599EB:
@ -2140,11 +2161,6 @@ static int ixgbe_set_flags(struct net_device *netdev, u32 data)
default:
break;
}
} else if (!adapter->rx_itr_setting) {
netdev->features &= ~NETIF_F_LRO;
if (data & ETH_FLAG_LRO)
e_info(probe, "rx-usecs set to 0, "
"LRO/RSC cannot be enabled.\n");
}
}