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e1000e: reduce writes of RX producer ptr 

Reduce number of writes to RX producer pointer.   When alloc'ing RX
buffers, only write the RX producer pointer once every
E1000_RX_BUFFER_WRITE (16) buffers created.

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2010-05-05 14:02:49 +00:00 committed by David S. Miller
parent 9ed318d546
commit 50849d792b
1 changed files with 23 additions and 34 deletions
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57
drivers/net/e1000e/netdev.c
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@ -548,26 +548,23 @@ static void e1000_alloc_rx_buffers(struct e1000_adapter *adapter,
rx_desc = E1000_RX_DESC(*rx_ring, i);
rx_desc->buffer_addr = cpu_to_le64(buffer_info->dma);
if (unlikely(!(i & (E1000_RX_BUFFER_WRITE - 1)))) {
/*
* Force memory writes to complete before letting h/w
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64).
*/
wmb();
writel(i, adapter->hw.hw_addr + rx_ring->tail);
}
i++;
if (i == rx_ring->count)
i = 0;
buffer_info = &rx_ring->buffer_info[i];
}
if (rx_ring->next_to_use != i) {
rx_ring->next_to_use = i;
if (i-- == 0)
i = (rx_ring->count - 1);
/*
* Force memory writes to complete before letting h/w
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64).
*/
wmb();
writel(i, adapter->hw.hw_addr + rx_ring->tail);
}
rx_ring->next_to_use = i;
}
/**
@ -649,6 +646,17 @@ static void e1000_alloc_rx_buffers_ps(struct e1000_adapter *adapter,
rx_desc->read.buffer_addr[0] = cpu_to_le64(buffer_info->dma);
if (unlikely(!(i & (E1000_RX_BUFFER_WRITE - 1)))) {
/*
* Force memory writes to complete before letting h/w
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64).
*/
wmb();
writel(i<<1, adapter->hw.hw_addr + rx_ring->tail);
}
i++;
if (i == rx_ring->count)
i = 0;
@ -656,26 +664,7 @@ static void e1000_alloc_rx_buffers_ps(struct e1000_adapter *adapter,
}
no_buffers:
if (rx_ring->next_to_use != i) {
rx_ring->next_to_use = i;
if (!(i--))
i = (rx_ring->count - 1);
/*
* Force memory writes to complete before letting h/w
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64).
*/
wmb();
/*
* Hardware increments by 16 bytes, but packet split
* descriptors are 32 bytes...so we increment tail
* twice as much.
*/
writel(i<<1, adapter->hw.hw_addr + rx_ring->tail);
}
rx_ring->next_to_use = i;
}
/**