From: dhananjay@netxen.com Date: Wed, 26 Dec 2007 18:23:58 +0000 (-0800) Subject: netxen: optimize tx handling X-Git-Tag: v2.6.24-rc8~34^2~11 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=53a01e00f8c78bc5875e09aca7749ea54bb09798;p=linux-2.6 netxen: optimize tx handling netxen driver allows limited number of threads simultaneously posting skb's in tx ring. If transmit slot is unavailable, driver calls schedule() or loops in xmit_frame(). This patch returns TX_BUSY and lets the stack reschedule the packet if transmit slot is unavailable. Also removes unnecessary check for tx timeout in the driver itself, the network stack does that anyway. Signed-off-by: Dhananjay Phadke Signed-off-by: Jeff Garzik --- diff --git a/drivers/net/netxen/netxen_nic_init.c b/drivers/net/netxen/netxen_nic_init.c index 3758926529..5f85ad686c 100644 --- a/drivers/net/netxen/netxen_nic_init.c +++ b/drivers/net/netxen/netxen_nic_init.c @@ -1248,7 +1248,6 @@ int netxen_process_cmd_ring(unsigned long data) struct pci_dev *pdev; struct netxen_skb_frag *frag; u32 i; - struct sk_buff *skb = NULL; int done; spin_lock(&adapter->tx_lock); @@ -1278,9 +1277,8 @@ int netxen_process_cmd_ring(unsigned long data) while ((last_consumer != consumer) && (count1 < MAX_STATUS_HANDLE)) { buffer = &adapter->cmd_buf_arr[last_consumer]; pdev = adapter->pdev; - frag = &buffer->frag_array[0]; - skb = buffer->skb; - if (skb && (cmpxchg(&buffer->skb, skb, 0) == skb)) { + if (buffer->skb) { + frag = &buffer->frag_array[0]; pci_unmap_single(pdev, frag->dma, frag->length, PCI_DMA_TODEVICE); frag->dma = 0ULL; @@ -1293,8 +1291,8 @@ int netxen_process_cmd_ring(unsigned long data) } adapter->stats.skbfreed++; - dev_kfree_skb_any(skb); - skb = NULL; + dev_kfree_skb_any(buffer->skb); + buffer->skb = NULL; } else if (adapter->proc_cmd_buf_counter == 1) { adapter->stats.txnullskb++; } diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c index 2d75c710f6..cec9e04f51 100644 --- a/drivers/net/netxen/netxen_nic_main.c +++ b/drivers/net/netxen/netxen_nic_main.c @@ -994,28 +994,6 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) return NETDEV_TX_OK; } - /* - * Everything is set up. Now, we just need to transmit it out. - * Note that we have to copy the contents of buffer over to - * right place. Later on, this can be optimized out by de-coupling the - * producer index from the buffer index. - */ - retry_getting_window: - spin_lock_bh(&adapter->tx_lock); - if (adapter->total_threads >= MAX_XMIT_PRODUCERS) { - spin_unlock_bh(&adapter->tx_lock); - /* - * Yield CPU - */ - if (!in_atomic()) - schedule(); - else { - for (i = 0; i < 20; i++) - cpu_relax(); /*This a nop instr on i386 */ - } - goto retry_getting_window; - } - local_producer = adapter->cmd_producer; /* There 4 fragments per descriptor */ no_of_desc = (frag_count + 3) >> 2; if (netdev->features & NETIF_F_TSO) { @@ -1029,16 +1007,19 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) } } } + + spin_lock_bh(&adapter->tx_lock); + if (adapter->total_threads >= MAX_XMIT_PRODUCERS) { + goto out_requeue; + } + local_producer = adapter->cmd_producer; k = adapter->cmd_producer; max_tx_desc_count = adapter->max_tx_desc_count; last_cmd_consumer = adapter->last_cmd_consumer; if ((k + no_of_desc) >= ((last_cmd_consumer <= k) ? last_cmd_consumer + max_tx_desc_count : last_cmd_consumer)) { - netif_stop_queue(netdev); - adapter->flags |= NETXEN_NETDEV_STATUS; - spin_unlock_bh(&adapter->tx_lock); - return NETDEV_TX_BUSY; + goto out_requeue; } k = get_index_range(k, max_tx_desc_count, no_of_desc); adapter->cmd_producer = k; @@ -1091,6 +1072,8 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) adapter->max_tx_desc_count); hwdesc = &hw->cmd_desc_head[producer]; memset(hwdesc, 0, sizeof(struct cmd_desc_type0)); + pbuf = &adapter->cmd_buf_arr[producer]; + pbuf->skb = NULL; } frag = &skb_shinfo(skb)->frags[i - 1]; len = frag->size; @@ -1146,6 +1129,8 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) } /* copy the MAC/IP/TCP headers to the cmd descriptor list */ hwdesc = &hw->cmd_desc_head[producer]; + pbuf = &adapter->cmd_buf_arr[producer]; + pbuf->skb = NULL; /* copy the first 64 bytes */ memcpy(((void *)hwdesc) + 2, @@ -1154,6 +1139,8 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) if (more_hdr) { hwdesc = &hw->cmd_desc_head[producer]; + pbuf = &adapter->cmd_buf_arr[producer]; + pbuf->skb = NULL; /* copy the next 64 bytes - should be enough except * for pathological case */ @@ -1187,14 +1174,17 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) } adapter->stats.xmitfinished++; - spin_unlock_bh(&adapter->tx_lock); - netdev->trans_start = jiffies; - DPRINTK(INFO, "wrote CMD producer %x to phantom\n", producer); - - DPRINTK(INFO, "Done. Send\n"); + spin_unlock_bh(&adapter->tx_lock); return NETDEV_TX_OK; + +out_requeue: + netif_stop_queue(netdev); + adapter->flags |= NETXEN_NETDEV_STATUS; + + spin_unlock_bh(&adapter->tx_lock); + return NETDEV_TX_BUSY; } static void netxen_watchdog(unsigned long v)