[ofa-general] [PATCH 10/10 REV5] [E1000] Implement batching
Krishna Kumar
krkumar2 at in.ibm.com
Fri Sep 14 02:04:42 PDT 2007
E1000: Implement batching capability (ported thanks to changes taken from
Jamal).
Signed-off-by: Krishna Kumar <krkumar2 at in.ibm.com>
---
e1000_main.c | 104 ++++++++++++++++++++++++++++++++++++++++++-----------------
1 files changed, 75 insertions(+), 29 deletions(-)
diff -ruNp org/drivers/net/e1000/e1000_main.c new/drivers/net/e1000/e1000_main.c
--- org/drivers/net/e1000/e1000_main.c 2007-09-14 10:30:57.000000000 +0530
+++ new/drivers/net/e1000/e1000_main.c 2007-09-14 10:31:02.000000000 +0530
@@ -990,7 +990,7 @@ e1000_probe(struct pci_dev *pdev,
if (pci_using_dac)
netdev->features |= NETIF_F_HIGHDMA;
- netdev->features |= NETIF_F_LLTX;
+ netdev->features |= NETIF_F_LLTX | NETIF_F_BATCH_SKBS;
adapter->en_mng_pt = e1000_enable_mng_pass_thru(&adapter->hw);
@@ -3092,6 +3092,17 @@ e1000_tx_map(struct e1000_adapter *adapt
return count;
}
+static void e1000_kick_DMA(struct e1000_adapter *adapter,
+ struct e1000_tx_ring *tx_ring, int i)
+{
+ wmb();
+
+ writel(i, adapter->hw.hw_addr + tx_ring->tdt);
+ /* we need this if more than one processor can write to our tail
+ * at a time, it syncronizes IO on IA64/Altix systems */
+ mmiowb();
+}
+
static void
e1000_tx_queue(struct e1000_adapter *adapter, struct e1000_tx_ring *tx_ring,
int tx_flags, int count)
@@ -3138,13 +3149,7 @@ e1000_tx_queue(struct e1000_adapter *ada
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64). */
- wmb();
-
tx_ring->next_to_use = i;
- writel(i, adapter->hw.hw_addr + tx_ring->tdt);
- /* we need this if more than one processor can write to our tail
- * at a time, it syncronizes IO on IA64/Altix systems */
- mmiowb();
}
/**
@@ -3251,22 +3256,23 @@ static int e1000_maybe_stop_tx(struct ne
}
#define TXD_USE_COUNT(S, X) (((S) >> (X)) + 1 )
+
+#define NETDEV_TX_DROPPED -5
+
static int
-e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
+e1000_prep_queue_frame(struct sk_buff *skb, struct net_device *netdev)
{
struct e1000_adapter *adapter = netdev_priv(netdev);
struct e1000_tx_ring *tx_ring;
unsigned int first, max_per_txd = E1000_MAX_DATA_PER_TXD;
unsigned int max_txd_pwr = E1000_MAX_TXD_PWR;
unsigned int tx_flags = 0;
- unsigned int len = skb->len;
- unsigned long flags;
- unsigned int nr_frags = 0;
- unsigned int mss = 0;
+ unsigned int len = skb->len - skb->data_len;
+ unsigned int nr_frags;
+ unsigned int mss;
int count = 0;
int tso;
unsigned int f;
- len -= skb->data_len;
/* This goes back to the question of how to logically map a tx queue
* to a flow. Right now, performance is impacted slightly negatively
@@ -3276,7 +3282,7 @@ e1000_xmit_frame(struct sk_buff *skb, st
if (unlikely(skb->len <= 0)) {
dev_kfree_skb_any(skb);
- return NETDEV_TX_OK;
+ return NETDEV_TX_DROPPED;
}
/* 82571 and newer doesn't need the workaround that limited descriptor
@@ -3322,7 +3328,7 @@ e1000_xmit_frame(struct sk_buff *skb, st
DPRINTK(DRV, ERR,
"__pskb_pull_tail failed.\n");
dev_kfree_skb_any(skb);
- return NETDEV_TX_OK;
+ return NETDEV_TX_DROPPED;
}
len = skb->len - skb->data_len;
break;
@@ -3366,22 +3372,15 @@ e1000_xmit_frame(struct sk_buff *skb, st
(adapter->hw.mac_type == e1000_82573))
e1000_transfer_dhcp_info(adapter, skb);
- if (!spin_trylock_irqsave(&tx_ring->tx_lock, flags))
- /* Collision - tell upper layer to requeue */
- return NETDEV_TX_LOCKED;
-
/* need: count + 2 desc gap to keep tail from touching
* head, otherwise try next time */
- if (unlikely(e1000_maybe_stop_tx(netdev, tx_ring, count + 2))) {
- spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
+ if (unlikely(e1000_maybe_stop_tx(netdev, tx_ring, count + 2)))
return NETDEV_TX_BUSY;
- }
if (unlikely(adapter->hw.mac_type == e1000_82547)) {
if (unlikely(e1000_82547_fifo_workaround(adapter, skb))) {
netif_stop_queue(netdev);
mod_timer(&adapter->tx_fifo_stall_timer, jiffies + 1);
- spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
return NETDEV_TX_BUSY;
}
}
@@ -3396,8 +3395,7 @@ e1000_xmit_frame(struct sk_buff *skb, st
tso = e1000_tso(adapter, tx_ring, skb);
if (tso < 0) {
dev_kfree_skb_any(skb);
- spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
- return NETDEV_TX_OK;
+ return NETDEV_TX_DROPPED;
}
if (likely(tso)) {
@@ -3416,13 +3414,61 @@ e1000_xmit_frame(struct sk_buff *skb, st
e1000_tx_map(adapter, tx_ring, skb, first,
max_per_txd, nr_frags, mss));
- netdev->trans_start = jiffies;
+ return NETDEV_TX_OK;
+}
+
+static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
+{
+ struct e1000_adapter *adapter = netdev_priv(netdev);
+ struct e1000_tx_ring *tx_ring = adapter->tx_ring;
+ struct sk_buff_head *blist;
+ int ret, skbs_done = 0;
+ unsigned long flags;
+
+ if (!spin_trylock_irqsave(&tx_ring->tx_lock, flags)) {
+ /* Collision - tell upper layer to requeue */
+ return NETDEV_TX_LOCKED;
+ }
- /* Make sure there is space in the ring for the next send. */
- e1000_maybe_stop_tx(netdev, tx_ring, MAX_SKB_FRAGS + 2);
+ blist = netdev->skb_blist;
+
+ if (!skb || (blist && skb_queue_len(blist))) {
+ /*
+ * Either batching xmit call, or single skb case but there are
+ * skbs already in the batch list from previous failure to
+ * xmit - send the earlier skbs first to avoid out of order.
+ */
+ if (skb)
+ __skb_queue_tail(blist, skb);
+ skb = __skb_dequeue(blist);
+ } else {
+ blist = NULL;
+ }
+
+ do {
+ ret = e1000_prep_queue_frame(skb, netdev);
+ if (likely(ret == NETDEV_TX_OK))
+ skbs_done++;
+ else {
+ if (ret == NETDEV_TX_BUSY) {
+ if (blist)
+ __skb_queue_head(blist, skb);
+ break;
+ }
+ /* skb dropped, not a TX error */
+ ret = NETDEV_TX_OK;
+ }
+ } while (blist && (skb = __skb_dequeue(blist)) != NULL);
+
+ if (skbs_done) {
+ e1000_kick_DMA(adapter, tx_ring, adapter->tx_ring->next_to_use);
+ netdev->trans_start = jiffies;
+ /* Make sure there is space in the ring for the next send. */
+ e1000_maybe_stop_tx(netdev, tx_ring, MAX_SKB_FRAGS + 2);
+ }
spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
- return NETDEV_TX_OK;
+ return ret;
}
/**
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