From: Jesper Dangaard Brouer <redacted>
Date: Wed, 27 Aug 2014 14:19:18 +0200

On Mon, 25 Aug 2014 16:34:58 -0700 (PDT)
David Miller [off-list ref] wrote:

quoted

Given Jesper's performance numbers, it's not the way to go.

Instead, go with a signalling scheme via new boolean skb->xmit_more.

This has several advantages:

1) Nearly trivial driver support, just protect the tail pointer
   update with the skb->xmit_more check.

2) No extra indirect calls in the non-deferral cases.

Even-though it is obvious that this new API skb->xmit_more will not
hurt performance, especially given skb->xmit_more is always 0 in this
kernel, I've still run my pktgen performance tests.

Compared to baseline[1]: (averaged 5609929 pps) (details below signature)
 * (1/5609929*10^9)-(1/5603728*10^9) = -0.197ns

As expected, this API does not hurt performance (as -0.197ns is below
our accuracy levels).

[1] http://thread.gmane.org/gmane.linux.network/327254/focus=327838

Thanks for validating Jesper :-)