[E1000-devel] [PATCH 2/2] ixgbe: fix parameters in distributing budget to each RX queue fairly

[Jing Zhang]

[1] share to each RX queue, given budget, is computed as fair as possible.
[2] queues are polled as much as budget approves.

Signed-off-by: Jing Zhang <zj.na...@gmail.com>
---

--- linux-2.6.34/drivers/net/ixgbe/ixgbe_main.c 2010-05-17
05:17:36.000000000 +0800
+++ ixgbe/ixgbe_main_02.c 2010-07-15 21:10:20.000000000 +0800
@@ -1538,6 +1538,9 @@ static int ixgbe_clean_rxtx_many(struct
  struct ixgbe_adapter *adapter = q_vector->adapter;
  struct ixgbe_ring *ring = NULL;
  int work_done = 0, i;
+ int fair_budget;
+ int this_budget;
+ int residual;
  long r_idx;
  bool tx_clean_complete = true;

@@ -1555,16 +1558,35 @@ static int ixgbe_clean_rxtx_many(struct

  /* attempt to distribute budget to each queue fairly, but don't allow
  * the budget to go below 1 because we'll exit polling */
- budget /= (q_vector->rxr_count ?: 1);
- budget = max(budget, 1);
+ if (q_vector->rxr_count && budget >= q_vector->rxr_count) {
+ this_budget =
+ fair_budget = budget / q_vector->rxr_count;
+ residual = budget - fair_budget * q_vector->rxr_count;
+ } else {
+ this_budget =
+ fair_budget = 1;
+ residual = 0;
+ }
+ if (residual > 0) {
+ this_budget++;
+ residual--;
+ }
  r_idx = find_first_bit(q_vector->rxr_idx, adapter->num_rx_queues);
  for (i = 0; i < q_vector->rxr_count; i++) {
+ int this_work = 0;
  ring = adapter->rx_ring[r_idx];
 #ifdef CONFIG_IXGBE_DCA
  if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
  ixgbe_update_rx_dca(adapter, ring);
 #endif
- ixgbe_clean_rx_irq(q_vector, ring, &work_done, budget);
+ ixgbe_clean_rx_irq(q_vector, ring, &this_work, this_budget);
+ work_done += this_work;
+ /* take extra works if any */
+ this_budget = fair_budget + this_budget - this_work;
+ if (residual > 0) {
+ this_budget++;
+ residual--;
+ }
  r_idx = find_next_bit(q_vector->rxr_idx, adapter->num_rx_queues,
                       r_idx + 1);
  }

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