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From: Olof Johansson <olof@lixom•net>
To: jgarzik@pobox•com
Cc: netdev@vger•kernel.org, linuxppc-dev@ozlabs•org
Subject: [PATCH] [06/10] pasemi_mac: Batch up TX buffer frees
Date: Wed, 22 Aug 2007 09:13:03 -0500	[thread overview]
Message-ID: <20070822141303.GG16830@lixom.net> (raw)
In-Reply-To: 20070817205413.548020000@lixom.net

[-- Attachment #1: pasemi_mac-tx-lock-reduction --]
[-- Type: text/plain, Size: 2158 bytes --]

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>

Index: mainline/drivers/net/pasemi_mac.c
===================================================================
--- mainline.orig/drivers/net/pasemi_mac.c
+++ mainline/drivers/net/pasemi_mac.c
@@ -561,37 +561,56 @@ static int pasemi_mac_clean_tx(struct pa
 	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;
 }
 
 
@@ -787,7 +806,7 @@ static int pasemi_mac_open(struct net_de
 			   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);

--

  parent reply	other threads:[~2007-08-22 15:16 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20070817205413.548020000@lixom.net>
2007-08-22 14:12 ` [PATCH] [01/10] pasemi_mac: Abstract out register access Olof Johansson
2007-08-31 13:50   ` Jeff Garzik
2007-08-22 14:12 ` [PATCH] [02/10] pasemi_mac: Stop using the pci config space accessors for register read/writes Olof Johansson
2007-08-23  0:31   ` Stephen Rothwell
2007-08-23 18:12     ` Olof Johansson
2007-08-23 18:13   ` [PATCH v2] " Olof Johansson
2007-08-24  4:05     ` Stephen Rothwell
2007-08-24 18:11       ` Olof Johansson
2007-08-25  1:19         ` Stephen Rothwell
2007-08-31 13:54     ` Jeff Garzik
2007-08-22 14:12 ` [PATCH] [03/10] pasemi_mac: Enable L2 caching of packet headers Olof Johansson
2007-08-22 14:12 ` [PATCH] [04/10] pasemi_mac: Fix memcpy amount for short receives Olof Johansson
2007-08-22 14:12 ` [PATCH] [05/10] pasemi_mac: RX performance tweaks Olof Johansson
2007-08-22 14:13 ` Olof Johansson [this message]
2007-08-22 14:13 ` [PATCH] [07/10] pasemi_mac: Enable LLTX Olof Johansson
2007-08-22 14:13 ` [PATCH] [08/10] pasemi_mac: Fix TX ring wrap checking Olof Johansson
2007-08-22 14:13 ` [PATCH] [09/10] pasemi_mac: Fix RX checksum flags Olof Johansson
2007-08-22 14:13 ` [PATCH] [10/10] pasemi_mac: Clean TX ring in poll Olof Johansson

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