Messages in this thread | | | From | (Alan Cox) | Subject | Re: Speed of memcpy, csum_partial and csum_partial_copy | Date | Sun, 9 Jun 1996 10:32:55 +0100 (BST) |
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> On the TCP i've been seting up for 2.1 there is no need for copy > number 2 since the skb is cloned (the copy is restricted to the skb > header).
Providing tcp.c doesnt scribble into the packet itself then yes this is true. Consider however a packet that is source routed via loopback then out. You will then need to rejig the header.
> Well, gonna try removing that copy you mention to see if it increases > performance. Is it done on the loopback device itself ?
Yes. I think we need to clone things more and drop code in the forwarding routines along the line of
newskb=skb_unshare(skb); /* in case its a clone */ if(!skb) dropit(skb); else { scribble_on_packet(); sendit(); }
which solves the issues with network taps as well.
Alan
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