[ofa-general] Re: [PATCH 10/10 Rev4] [E1000] Implement batching
Kok, Auke
auke-jan.h.kok at intel.com
Wed Aug 22 07:39:31 PDT 2007
Krishna Kumar wrote:
> E1000: Implement batching capability (ported thanks to changes taken from
> Jamal). Not all changes are made in this as in IPoIB, eg, handling
> out of order skbs (see XXX in the first mail).
>
> Signed-off-by: Krishna Kumar <krkumar2 at in.ibm.com>
> ---
> e1000_main.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++------------
> 1 files changed, 121 insertions(+), 29 deletions(-)
Krishna,
while I appreciate the patch I would have preferred a patch to e1000e. Not only
does the e1000e driver remove a lot of the workarounds for old silicon, it is
also a good way for us to move the current e1000 driver into a bit more stable
maintenance mode.
Do you think you can write this patch for e1000e instead? code-wise a lot of
things are still the same, so your patch should be relatively easy to generate.
e1000e currently lives in a branch from jeff garzik's netdev-2.6 tree
Thanks,
Auke
>
> diff -ruNp org/drivers/net/e1000/e1000_main.c new/drivers/net/e1000/e1000_main.c
> --- org/drivers/net/e1000/e1000_main.c 2007-08-20 14:26:29.000000000 +0530
> +++ new/drivers/net/e1000/e1000_main.c 2007-08-22 08:33:51.000000000 +0530
> @@ -157,6 +157,7 @@ static void e1000_update_phy_info(unsign
> static void e1000_watchdog(unsigned long data);
> static void e1000_82547_tx_fifo_stall(unsigned long data);
> static int e1000_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
> +static int e1000_xmit_frames(struct net_device *dev);
> static struct net_device_stats * e1000_get_stats(struct net_device *netdev);
> static int e1000_change_mtu(struct net_device *netdev, int new_mtu);
> static int e1000_set_mac(struct net_device *netdev, void *p);
> @@ -990,7 +991,7 @@ 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);
>
> @@ -3098,6 +3099,18 @@ 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)
> @@ -3144,13 +3157,7 @@ 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();
> }
>
> /**
> @@ -3257,21 +3264,31 @@ static int e1000_maybe_stop_tx(struct ne
> }
>
> #define TXD_USE_COUNT(S, X) (((S) >> (X)) + 1 )
> +
> +struct e1000_tx_cbdata {
> + int count;
> + unsigned int max_per_txd;
> + unsigned int nr_frags;
> + unsigned int mss;
> +};
> +
> +#define E1000_SKB_CB(__skb) ((struct e1000_tx_cbdata *)&((__skb)->cb[0]))
> +#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_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 nr_frags;
> + unsigned int mss;
> int count = 0;
> - int tso;
> unsigned int f;
> + struct e1000_tx_cbdata *cb = E1000_SKB_CB(skb);
> +
> len -= skb->data_len;
>
> /* This goes back to the question of how to logically map a tx queue
> @@ -3282,7 +3299,7 @@ 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
> @@ -3328,7 +3345,7 @@ 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;
> @@ -3372,22 +3389,32 @@ 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;
> + cb->count = count;
> + cb->max_per_txd = max_per_txd;
> + cb->nr_frags = nr_frags;
> + cb->mss = mss;
> +
> + return NETDEV_TX_OK;
> +}
> +
> +static int e1000_queue_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;
> + int tso;
> + unsigned int first;
> + unsigned int tx_flags = 0;
> + struct e1000_tx_cbdata *cb = E1000_SKB_CB(skb);
>
> /* 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, cb->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;
> }
> }
> @@ -3402,8 +3429,7 @@ 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)) {
> @@ -3420,12 +3446,78 @@ e1000_xmit_frame(struct sk_buff *skb, st
>
> e1000_tx_queue(adapter, tx_ring, tx_flags,
> e1000_tx_map(adapter, tx_ring, skb, first,
> - max_per_txd, nr_frags, mss));
> + cb->max_per_txd, cb->nr_frags, cb->mss));
> +
> + return NETDEV_TX_OK;
> +}
>
> - netdev->trans_start = jiffies;
> +static inline int e1000_xmit_frames(struct net_device *netdev)
> +{
> + struct e1000_adapter *adapter = netdev->priv;
> + struct e1000_tx_ring *tx_ring = adapter->tx_ring;
> + int ret = NETDEV_TX_OK;
> + int skbs_done = 0;
> + struct sk_buff *skb;
> + 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);
> + while ((skb = __skb_dequeue(netdev->skb_blist)) != NULL) {
> + if ((ret = e1000_prep_queue_frame(skb, netdev)) != NETDEV_TX_OK)
> + continue;
> +
> + ret = e1000_queue_frame(skb, netdev);
> + if (ret == NETDEV_TX_OK) {
> + skbs_done++;
> + } else {
> + if (ret == NETDEV_TX_BUSY)
> + __skb_queue_head(netdev->skb_blist, skb);
> + break;
> + }
> + }
> +
> + if (skbs_done) {
> + e1000_kick_DMA(adapter, tx_ring, adapter->tx_ring->next_to_use);
> + netdev->trans_start = jiffies;
> + e1000_maybe_stop_tx(netdev, tx_ring, MAX_SKB_FRAGS + 2);
> + }
> +
> + spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
> +
> + if (ret == NETDEV_TX_DROPPED)
> + ret = NETDEV_TX_OK;
> +
> + return ret;
> +}
> +
> +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;
> + unsigned long flags;
> +
> + if (!skb)
> + return e1000_xmit_frames(netdev);
> +
> + if (!spin_trylock_irqsave(&tx_ring->tx_lock, flags)) {
> + /* Collision - tell upper layer to requeue */
> + return NETDEV_TX_LOCKED;
> + }
> +
> + if (unlikely(e1000_prep_queue_frame(skb, netdev) != NETDEV_TX_OK)) {
> + spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
> + return NETDEV_TX_OK;
> + }
> +
> + if (e1000_queue_frame(skb, netdev) == NETDEV_TX_OK) {
> + 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;
> -
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