pasemi_mac: Batch up TX buffer frees

Postpone pci unmap and skb free of the transmitted buffers to outside of
the tx ring lock, batching them up 32 at a time.

Also increase the count threshold to 128.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index f71a686..4836d40 100644 (file)
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -551,37 +551,56 @@ static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
        int i;
        struct pasemi_mac_buffer *info;
        struct pas_dma_xct_descr *dp;
-       int start, count;
+       unsigned int start, count, limit;
+       unsigned int total_count;
        int flags;
+       struct sk_buff *skbs[32];
+       dma_addr_t dmas[32];
 
+       total_count = 0;
+restart:
        spin_lock_irqsave(&mac->tx->lock, flags);
 
        start = mac->tx->next_to_clean;
+       limit = min(mac->tx->next_to_use, start+32);
+
        count = 0;
 
-       for (i = start; i < mac->tx->next_to_use; i++) {
+       for (i = start; i < limit; i++) {
                dp = &TX_DESC(mac, i);
+
                if (unlikely(dp->mactx & XCT_MACTX_O))
+                       /* Not yet transmitted */
                        break;
 
-               count++;
-
                info = &TX_DESC_INFO(mac, i);
-
-               pci_unmap_single(mac->dma_pdev, info->dma,
-                                info->skb->len, PCI_DMA_TODEVICE);
-               dev_kfree_skb_irq(info->skb);
+               skbs[count] = info->skb;
+               dmas[count] = info->dma;
 
                info->skb = NULL;
                info->dma = 0;
                dp->mactx = 0;
                dp->ptr = 0;
+
+               count++;
        }
        mac->tx->next_to_clean += count;
        spin_unlock_irqrestore(&mac->tx->lock, flags);
        netif_wake_queue(mac->netdev);
 
-       return count;
+       for (i = 0; i < count; i++) {
+               pci_unmap_single(mac->dma_pdev, dmas[i],
+                                skbs[i]->len, PCI_DMA_TODEVICE);
+               dev_kfree_skb_irq(skbs[i]);
+       }
+
+       total_count += count;
+
+       /* If the batch was full, try to clean more */
+       if (count == 32)
+               goto restart;
+
+       return total_count;
 }
 
 
@@ -777,7 +796,7 @@ static int pasemi_mac_open(struct net_device *dev)
                           PAS_IOB_DMA_RXCH_CFG_CNTTH(0));
 
        write_iob_reg(mac, PAS_IOB_DMA_TXCH_CFG(mac->dma_txch),
-                          PAS_IOB_DMA_TXCH_CFG_CNTTH(32));
+                          PAS_IOB_DMA_TXCH_CFG_CNTTH(128));
 
        /* Clear out any residual packet count state from firmware */
        pasemi_mac_restart_rx_intr(mac);