[ofa-general] Re: [PATCH 10/10 REV5] [E1000] Implement batching
Kok, Auke
auke-jan.h.kok at intel.com
Tue Nov 13 13:28:14 PST 2007
Krishna Kumar wrote:
> E1000: Implement batching capability (ported thanks to changes taken from
> Jamal).
>
> Signed-off-by: Krishna Kumar <krkumar2 at in.ibm.com>
this doesn't apply anymore and it would help if you could re-spin this for e1000e.
I don't know what the status for merging of the batched xmit patches is right now
but it would help if you could rewrite them against e1000e, which I assume is what
most people want to test with. There are also significant changes upstream right
now in jgarzik/netdev-2.6 #upstream...
I'm still very interested in these patches BTW.
Auke
> ---
> 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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