Messages in this thread Patch in this message | | | From | Chris Leech <> | Subject | [PATCH 3/7] [I/OAT] Don't offload copies for loopback traffic | Date | Tue, 15 Aug 2006 17:53:41 -0700 |
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Local traffic (loopback) is generally in cache anyway, and the overhead cost of offloading the copy is worse than just doing it with the CPU.
Signed-off-by: Chris Leech <christopher.leech@intel.com> ---
net/ipv4/tcp.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 36f6b64..7971e73 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1107,6 +1107,7 @@ int tcp_recvmsg(struct kiocb *iocb, stru int copied_early = 0; int available = 0; struct sk_buff *skb; + struct dst_entry *dst; lock_sock(sk); @@ -1136,7 +1137,8 @@ int tcp_recvmsg(struct kiocb *iocb, stru skb = skb_peek_tail(&sk->sk_receive_queue); if (skb) available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); - if ((available < target) && + dst = __sk_dst_get(sk); + if ((available < target) && (!dst || (dst->dev != &loopback_dev)) && (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && !sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) { preempt_enable_no_resched(); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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