Optimize IPOIB CM receive flow
This patch tries to reduce the number of accesses to the skb
object and save CPU cycles and cache misses.
Signed-off-by: Eli Cohen <[EMAIL PROTECTED]>
Index: ofa_kernel-1.2.5/drivers/infiniband/ulp/ipoib/ipoib_cm.c
===================================================================
--- ofa_kernel-1.2.5.orig/drivers/infiniband/ulp/ipoib/ipoib_cm.c
2007-10-10 15:10:27.000000000 +0200
+++ ofa_kernel-1.2.5/drivers/infiniband/ulp/ipoib/ipoib_cm.c 2007-10-10
15:35:01.000000000 +0200
@@ -374,6 +374,8 @@ static void skb_put_frags(struct sk_buff
{
int i, num_frags;
unsigned int size;
+ int unused_frags = 0;
+ unsigned int used_size = 0;
/* put header into skb */
size = min(length, hdr_space);
@@ -382,23 +384,25 @@ static void skb_put_frags(struct sk_buff
length -= size;
num_frags = skb_shinfo(skb)->nr_frags;
- for (i = 0; i < num_frags; i++) {
+ for (i = 0; i < num_frags; ++i) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
if (length == 0) {
/* don't need this page */
skb_fill_page_desc(toskb, i, frag->page, 0, PAGE_SIZE);
- --skb_shinfo(skb)->nr_frags;
+ ++unused_frags;
} else {
- size = min(length, (unsigned) PAGE_SIZE);
+ size = length & PAGE_MASK ? PAGE_SIZE : length &
(PAGE_SIZE - 1);
frag->size = size;
- skb->data_len += size;
- skb->truesize += size;
- skb->len += size;
+ used_size += size;
length -= size;
}
}
+ skb->data_len += used_size;
+ skb->truesize += used_size;
+ skb->len += used_size;
+ skb_shinfo(skb)->nr_frags -= unused_frags;
}
void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
@@ -437,7 +441,7 @@ void ipoib_cm_handle_rx_wc(struct net_de
goto repost;
}
- if (!likely(wr_id & IPOIB_CM_RX_UPDATE_MASK)) {
+ if (unlikely(wr_id & IPOIB_CM_RX_UPDATE_MASK)) {
p = wc->qp->qp_context;
if (p && time_after_eq(jiffies, p->jiffies +
IPOIB_CM_RX_UPDATE_TIME)) {
spin_lock_irqsave(&priv->lock, flags);
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