From: "Michael S. Tsirkin" <m...@redhat.com> Date: Sun, 22 Jul 2012 01:05:34 +0300
> I agree a small win in CPU use is nothing to write home about, > I don't yet understand why the win is so small - macvtap has zero copy > supported for a while and it has exactly same issues. > I hope adding tun zerocopy support upstream will help us > make progress faster and find the bottleneck, so far not many people use > macvtap so zero copy mode there didn't make progress. > > I do know why local performance regresses with zero copy enabled: > instead of plain copy to user we got get user pages and then memcpy. > We'll need some logic here to detect this and turn off zero copy. > > The core patches will also be helpful for Ian's more ambitious work. > > Overall I think it's a step in the right direction and it's easier to > work if core parts are upstream, but if you think we need to wait > until the gains are more significant, I understand that too. Ok, I've applied this series, let's see what happens. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
