On Tue, Sep 14, 2010 at 11:21:15PM -0700, Shirley Ma wrote: > On Wed, 2010-09-15 at 07:12 +0200, Michael S. Tsirkin wrote: > > Yes, I agree this patch is useful for demo purposes: > > simple, and shows what kind of performance gains > > we can expect for TX. > > Any other issue you can see in this patch beside vhost descriptors > update?
Another issue is that macvtap can be bound to almost anything, including e.g. a tap device or a bridge, which might hang on to skb fragments for unlimited time. Zero copy TX won't easily work there. I can imagine either somehow triggering a data copy after the fact (hard), or detecting such devices and avoiding zero copy (unfortunate for guest to guest, and drivers will need tuning). > Don't you think once I address vhost_add_used_and_signal update > issue, it is a simple and complete patch for macvtap TX zero copy? > > Thanks > Shirley I like the fact that the patch is simple. Unfortunately I suspect it'll stop being simple by the time it's complete :) -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
