Re: Slow speed of tcp connections in a network namespace

[Eric Dumazet <eric.dumazet@gmail.com>]

Le samedi 29 décembre 2012 à 09:40 -0800, Eric Dumazet a écrit :

> 
> Please post your new tcpdump then ;)
> 
> also post "netstat -s" from root and test ns after your wgets

Also try following bnx2 patch.

It should help GRO / TCP coalesce

bnx2 should be the last driver not using skb head_frag


diff --git a/drivers/net/ethernet/broadcom/bnx2.c b/drivers/net/ethernet/broadcom/bnx2.c
index a1adfaf..08a2d40 100644
--- a/drivers/net/ethernet/broadcom/bnx2.c
+++ b/drivers/net/ethernet/broadcom/bnx2.c
@@ -2726,6 +2726,14 @@ bnx2_free_rx_page(struct bnx2 *bp, struct bnx2_rx_ring_info *rxr, u16 index)
 	rx_pg->page = NULL;
 }
 
+static void bnx2_frag_free(const struct bnx2 *bp, void *data)
+{
+	if (bp->rx_frag_size)
+		put_page(virt_to_head_page(data));
+	else
+		kfree(data);
+}
+
 static inline int
 bnx2_alloc_rx_data(struct bnx2 *bp, struct bnx2_rx_ring_info *rxr, u16 index, gfp_t gfp)
 {
@@ -2735,7 +2743,10 @@ bnx2_alloc_rx_data(struct bnx2 *bp, struct bnx2_rx_ring_info *rxr, u16 index, gf
 	struct bnx2_rx_bd *rxbd =
 		&rxr->rx_desc_ring[BNX2_RX_RING(index)][BNX2_RX_IDX(index)];
 
-	data = kmalloc(bp->rx_buf_size, gfp);
+	if (bp->rx_frag_size)
+		data = netdev_alloc_frag(bp->rx_frag_size);
+	else
+		data = kmalloc(bp->rx_buf_size, gfp);
 	if (!data)
 		return -ENOMEM;
 
@@ -2744,7 +2755,7 @@ bnx2_alloc_rx_data(struct bnx2 *bp, struct bnx2_rx_ring_info *rxr, u16 index, gf
 				 bp->rx_buf_use_size,
 				 PCI_DMA_FROMDEVICE);
 	if (dma_mapping_error(&bp->pdev->dev, mapping)) {
-		kfree(data);
+		bnx2_frag_free(bp, data);
 		return -EIO;
 	}
 
@@ -3014,9 +3025,9 @@ error:
 
 	dma_unmap_single(&bp->pdev->dev, dma_addr, bp->rx_buf_use_size,
 			 PCI_DMA_FROMDEVICE);
-	skb = build_skb(data, 0);
+	skb = build_skb(data, bp->rx_frag_size);
 	if (!skb) {
-		kfree(data);
+		bnx2_frag_free(bp, data);
 		goto error;
 	}
 	skb_reserve(skb, ((u8 *)get_l2_fhdr(data) - data) + BNX2_RX_OFFSET);
@@ -5358,6 +5369,10 @@ bnx2_set_rx_ring_size(struct bnx2 *bp, u32 size)
 	/* hw alignment + build_skb() overhead*/
 	bp->rx_buf_size = SKB_DATA_ALIGN(bp->rx_buf_use_size + BNX2_RX_ALIGN) +
 		NET_SKB_PAD + SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	if (bp->rx_buf_size <= PAGE_SIZE)
+		bp->rx_frag_size = bp->rx_buf_size;
+	else
+		bp->rx_frag_size = 0;
 	bp->rx_jumbo_thresh = rx_size - BNX2_RX_OFFSET;
 	bp->rx_ring_size = size;
 	bp->rx_max_ring = bnx2_find_max_ring(size, BNX2_MAX_RX_RINGS);
@@ -5436,7 +5451,7 @@ bnx2_free_rx_skbs(struct bnx2 *bp)
 
 			rx_buf->data = NULL;
 
-			kfree(data);
+			bnx2_frag_free(bp, data);
 		}
 		for (j = 0; j < bp->rx_max_pg_ring_idx; j++)
 			bnx2_free_rx_page(bp, rxr, j);
diff --git a/drivers/net/ethernet/broadcom/bnx2.h b/drivers/net/ethernet/broadcom/bnx2.h
index 172efbe..11f5dee 100644
--- a/drivers/net/ethernet/broadcom/bnx2.h
+++ b/drivers/net/ethernet/broadcom/bnx2.h
@@ -6804,6 +6804,7 @@ struct bnx2 {
 
 	u32			rx_buf_use_size;	/* useable size */
 	u32			rx_buf_size;		/* with alignment */
+	u32			rx_frag_size; /* 0 if kmalloced(), or rx_buf_size */
 	u32			rx_copy_thresh;
 	u32			rx_jumbo_thresh;
 	u32			rx_max_ring_idx;