On Thu, Oct 06, 2011 at 11:18:28AM -0200, Michael S. Tsirkin wrote: > On Thu, Oct 06, 2011 at 12:15:36PM +1030, Rusty Russell wrote: > > On Wed, 05 Oct 2011 15:54:05 -0400, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > > Split virtqueue_kick to be able to do the actual notification outside the > > > lock protecting the virtqueue. This patch was originally done by > > > Stefan Hajnoczi, but I can't find the original one anymore and had to > > > recreated it from memory. Pointers to the original or corrections for > > > the commit message are welcome. > > > > An alternative to this is to update the ring on every virtqueue_add_buf. > > MST discussed this for virtio_net, and I think it's better in general. > > > > The only reason that it wasn't written that way originally is that the > > barriers make add_buf slightly more expensive. > > > > Cheers, > > Rusty. > > With event index, I'm not sure that's enough to make the kick lockless > anymore. Hmm, any comment on this? These have been benchmarked to give a sizeable speedup, so I'm thinking it's better to take the patches as is, if someone has the inclination to redo the work with an atomic virtqueue_add_buf, that can be applied on top. > > -- > MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
