igbvf: refactor Interrupt Throttle Rate code
The existing ITR code is broken and confusing, with lots of similarly-named
variables that do different things. Additionally, after the driver carefully
determines the optimal interrupt rate for the adapter, it then
ignores it and always writes a fixed, suboptimal value.
This patch refactors that code to make variable names more descriptive of
what they actually do, and then actually writes the calculated result to
the hardware.
Preliminary testing shows that netperf TCP_STREAM tests goes from ~918Mbps
to ~940Mbps, and TCP_RR goes from ~2k transactions/sec up to > 8k.
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Robert E Garrett <robertX.e.garrett@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c
index 4e9141c..446297f 100644
--- a/drivers/net/ethernet/intel/igbvf/netdev.c
+++ b/drivers/net/ethernet/intel/igbvf/netdev.c
@@ -632,14 +632,13 @@
* traffic pattern. Constants in this function were computed
* based on theoretical maximum wire speed and thresholds were set based
* on testing data as well as attempting to minimize response time
- * while increasing bulk throughput. This functionality is controlled
- * by the InterruptThrottleRate module parameter.
+ * while increasing bulk throughput.
**/
-static unsigned int igbvf_update_itr(struct igbvf_adapter *adapter,
- u16 itr_setting, int packets,
- int bytes)
+static enum latency_range igbvf_update_itr(struct igbvf_adapter *adapter,
+ enum latency_range itr_setting,
+ int packets, int bytes)
{
- unsigned int retval = itr_setting;
+ enum latency_range retval = itr_setting;
if (packets == 0)
goto update_itr_done;
@@ -675,65 +674,87 @@
retval = low_latency;
}
break;
+ default:
+ break;
}
update_itr_done:
return retval;
}
-static void igbvf_set_itr(struct igbvf_adapter *adapter)
+static int igbvf_range_to_itr(enum latency_range current_range)
{
- struct e1000_hw *hw = &adapter->hw;
- u16 current_itr;
- u32 new_itr = adapter->itr;
+ int new_itr;
- adapter->tx_itr = igbvf_update_itr(adapter, adapter->tx_itr,
- adapter->total_tx_packets,
- adapter->total_tx_bytes);
- /* conservative mode (itr 3) eliminates the lowest_latency setting */
- if (adapter->itr_setting == 3 && adapter->tx_itr == lowest_latency)
- adapter->tx_itr = low_latency;
-
- adapter->rx_itr = igbvf_update_itr(adapter, adapter->rx_itr,
- adapter->total_rx_packets,
- adapter->total_rx_bytes);
- /* conservative mode (itr 3) eliminates the lowest_latency setting */
- if (adapter->itr_setting == 3 && adapter->rx_itr == lowest_latency)
- adapter->rx_itr = low_latency;
-
- current_itr = max(adapter->rx_itr, adapter->tx_itr);
-
- switch (current_itr) {
+ switch (current_range) {
/* counts and packets in update_itr are dependent on these numbers */
case lowest_latency:
- new_itr = 70000;
+ new_itr = IGBVF_70K_ITR;
break;
case low_latency:
- new_itr = 20000; /* aka hwitr = ~200 */
+ new_itr = IGBVF_20K_ITR;
break;
case bulk_latency:
- new_itr = 4000;
+ new_itr = IGBVF_4K_ITR;
break;
default:
+ new_itr = IGBVF_START_ITR;
break;
}
+ return new_itr;
+}
- if (new_itr != adapter->itr) {
+static void igbvf_set_itr(struct igbvf_adapter *adapter)
+{
+ u32 new_itr;
+
+ adapter->tx_ring->itr_range =
+ igbvf_update_itr(adapter,
+ adapter->tx_ring->itr_val,
+ adapter->total_tx_packets,
+ adapter->total_tx_bytes);
+
+ /* conservative mode (itr 3) eliminates the lowest_latency setting */
+ if (adapter->requested_itr == 3 &&
+ adapter->tx_ring->itr_range == lowest_latency)
+ adapter->tx_ring->itr_range = low_latency;
+
+ new_itr = igbvf_range_to_itr(adapter->tx_ring->itr_range);
+
+
+ if (new_itr != adapter->tx_ring->itr_val) {
+ u32 current_itr = adapter->tx_ring->itr_val;
/*
* this attempts to bias the interrupt rate towards Bulk
* by adding intermediate steps when interrupt rate is
* increasing
*/
- new_itr = new_itr > adapter->itr ?
- min(adapter->itr + (new_itr >> 2), new_itr) :
- new_itr;
- adapter->itr = new_itr;
- adapter->rx_ring->itr_val = 1952;
+ new_itr = new_itr > current_itr ?
+ min(current_itr + (new_itr >> 2), new_itr) :
+ new_itr;
+ adapter->tx_ring->itr_val = new_itr;
- if (adapter->msix_entries)
- adapter->rx_ring->set_itr = 1;
- else
- ew32(ITR, 1952);
+ adapter->tx_ring->set_itr = 1;
+ }
+
+ adapter->rx_ring->itr_range =
+ igbvf_update_itr(adapter, adapter->rx_ring->itr_val,
+ adapter->total_rx_packets,
+ adapter->total_rx_bytes);
+ if (adapter->requested_itr == 3 &&
+ adapter->rx_ring->itr_range == lowest_latency)
+ adapter->rx_ring->itr_range = low_latency;
+
+ new_itr = igbvf_range_to_itr(adapter->rx_ring->itr_range);
+
+ if (new_itr != adapter->rx_ring->itr_val) {
+ u32 current_itr = adapter->rx_ring->itr_val;
+ new_itr = new_itr > current_itr ?
+ min(current_itr + (new_itr >> 2), new_itr) :
+ new_itr;
+ adapter->rx_ring->itr_val = new_itr;
+
+ adapter->rx_ring->set_itr = 1;
}
}
@@ -835,6 +856,11 @@
struct e1000_hw *hw = &adapter->hw;
struct igbvf_ring *tx_ring = adapter->tx_ring;
+ if (tx_ring->set_itr) {
+ writel(tx_ring->itr_val,
+ adapter->hw.hw_addr + tx_ring->itr_register);
+ adapter->tx_ring->set_itr = 0;
+ }
adapter->total_tx_bytes = 0;
adapter->total_tx_packets = 0;
@@ -937,19 +963,10 @@
igbvf_assign_vector(adapter, IGBVF_NO_QUEUE, 0, vector++);
adapter->eims_enable_mask |= tx_ring->eims_value;
- if (tx_ring->itr_val)
- writel(tx_ring->itr_val,
- hw->hw_addr + tx_ring->itr_register);
- else
- writel(1952, hw->hw_addr + tx_ring->itr_register);
-
+ writel(tx_ring->itr_val, hw->hw_addr + tx_ring->itr_register);
igbvf_assign_vector(adapter, 0, IGBVF_NO_QUEUE, vector++);
adapter->eims_enable_mask |= rx_ring->eims_value;
- if (rx_ring->itr_val)
- writel(rx_ring->itr_val,
- hw->hw_addr + rx_ring->itr_register);
- else
- writel(1952, hw->hw_addr + rx_ring->itr_register);
+ writel(rx_ring->itr_val, hw->hw_addr + rx_ring->itr_register);
/* set vector for other causes, i.e. link changes */
@@ -1027,7 +1044,7 @@
goto out;
adapter->tx_ring->itr_register = E1000_EITR(vector);
- adapter->tx_ring->itr_val = 1952;
+ adapter->tx_ring->itr_val = adapter->current_itr;
vector++;
err = request_irq(adapter->msix_entries[vector].vector,
@@ -1037,7 +1054,7 @@
goto out;
adapter->rx_ring->itr_register = E1000_EITR(vector);
- adapter->rx_ring->itr_val = 1952;
+ adapter->rx_ring->itr_val = adapter->current_itr;
vector++;
err = request_irq(adapter->msix_entries[vector].vector,
@@ -1151,7 +1168,7 @@
if (work_done < budget) {
napi_complete(napi);
- if (adapter->itr_setting & 3)
+ if (adapter->requested_itr & 3)
igbvf_set_itr(adapter);
if (!test_bit(__IGBVF_DOWN, &adapter->state))
@@ -1521,8 +1538,8 @@
adapter->tx_abs_int_delay = 32;
adapter->rx_int_delay = 0;
adapter->rx_abs_int_delay = 8;
- adapter->itr_setting = 3;
- adapter->itr = 20000;
+ adapter->requested_itr = 3;
+ adapter->current_itr = IGBVF_START_ITR;
/* Set various function pointers */
adapter->ei->init_ops(&adapter->hw);