Attaching the file
On Wed, 2007-07-18 at 15:25 +0300, Eli Cohen wrote:
> I made some experiments with iperf running on CM mode and TCP sockets. I
> can see that there is no bad affect on BW (excel file attached). We did
> see a slight improvement in packet loss in UDP mode with an application
> supplied by a customer.
>
>
>
> Copy small received patckets to newly allocated SKBs just
> big enough to contain the packet. This will relief accounting
> done on the socket so that a smaller size is used.
>
> Signed-off-by: Eli Cohen <[EMAIL PROTECTED]>
>
> ---
>
> Index: connectx_kernel/drivers/infiniband/ulp/ipoib/ipoib.h
> ===================================================================
> --- connectx_kernel.orig/drivers/infiniband/ulp/ipoib/ipoib.h 2007-07-17
> 15:41:29.000000000 +0300
> +++ connectx_kernel/drivers/infiniband/ulp/ipoib/ipoib.h 2007-07-18
> 09:34:49.000000000 +0300
> @@ -651,4 +651,7 @@
>
> #define IPOIB_QPN(ha) (be32_to_cpup((__be32 *) ha) & 0xffffff)
>
> +#define SKB_LEN_THOLD 256
> +#define CM_SKB_LEN_THOLD min(SKB_LEN_THOLD, IPOIB_CM_HEAD_SIZE)
> +
> #endif /* _IPOIB_H */
> Index: connectx_kernel/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> ===================================================================
> --- connectx_kernel.orig/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> 2007-07-17 15:41:29.000000000 +0300
> +++ connectx_kernel/drivers/infiniband/ulp/ipoib/ipoib_cm.c 2007-07-18
> 10:46:54.000000000 +0300
> @@ -452,26 +452,40 @@
>
> frags = PAGE_ALIGN(wc->byte_len - min(wc->byte_len,
> (unsigned)IPOIB_CM_HEAD_SIZE)) /
> PAGE_SIZE;
> -
> - newskb = ipoib_cm_alloc_rx_skb(dev, wr_id, frags, mapping);
> - if (unlikely(!newskb)) {
> - /*
> - * If we can't allocate a new RX buffer, dump
> - * this packet and reuse the old buffer.
> - */
> - ipoib_dbg(priv, "failed to allocate receive buffer %d\n",
> wr_id);
> - ++priv->stats.rx_dropped;
> - goto repost;
> + if (wc->byte_len < CM_SKB_LEN_THOLD) {
> + newskb = dev_alloc_skb(wc->byte_len);
> + if (!newskb)
> + ipoib_warn(priv, "failed to allocate skb\n");
> +
> + ib_dma_sync_single_for_cpu(priv->ca,
> priv->cm.srq_ring[wr_id].mapping[0],
> + IPOIB_CM_HEAD_SIZE, DMA_FROM_DEVICE);
> + skb_copy_from_linear_data_offset(skb, IB_GRH_BYTES,
> new_skb->data,
> + wc->byte_len - IB_GRH_BYTES);
> + ib_dma_sync_single_for_device(priv->ca,
> priv->cm.srq_ring[wr_id].mapping[0],
> + IPOIB_CM_HEAD_SIZE,
> DMA_FROM_DEVICE);
> +
> + skb_put(newskb, wc->byte_len);
> + skb = newskb;
> + }
> + else {
> + newskb = ipoib_cm_alloc_rx_skb(dev, wr_id, frags, mapping);
> + if (unlikely(!newskb)) {
> + /*
> + * If we can't allocate a new RX buffer, dump
> + * this packet and reuse the old buffer.
> + */
> + ipoib_dbg(priv, "failed to allocate receive buffer
> %d\n", wr_id);
> + ++priv->stats.rx_dropped;
> + goto repost;
> + }
> + ipoib_cm_dma_unmap_rx(priv, frags,
> priv->cm.srq_ring[wr_id].mapping);
> + memcpy(priv->cm.srq_ring[wr_id].mapping, mapping, (frags + 1) *
> sizeof *mapping);
> + skb_put_frags(skb, IPOIB_CM_HEAD_SIZE, wc->byte_len, newskb);
> }
>
> - ipoib_cm_dma_unmap_rx(priv, frags, priv->cm.srq_ring[wr_id].mapping);
> - memcpy(priv->cm.srq_ring[wr_id].mapping, mapping, (frags + 1) * sizeof
> *mapping);
> -
> ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
> wc->byte_len, wc->slid);
>
> - skb_put_frags(skb, IPOIB_CM_HEAD_SIZE, wc->byte_len, newskb);
> -
> skb->protocol = ((struct ipoib_header *) skb->data)->proto;
> skb_reset_mac_header(skb);
> skb_pull(skb, IPOIB_ENCAP_LEN);
>
skb_vs_noskb_patch.xls
Description: MS-Excel spreadsheet
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