On Thu, 01 Oct 2015 11:42:23 +0200 Vincent JARDIN <vincent.jardin at 6wind.com> wrote:
> On 01/10/2015 11:22, Avi Kivity wrote: > >> As far as I could see, without this kind of motivation, people do not > >> even want to try. > > > > You are mistaken. The problem is a lot harder than you think. > > > > People didn't go and write userspace drivers because they were lazy. > > They wrote them because there was no other way. > > I disagree, it is possible to write a 'partial' userspace driver. > > Here it is an example: > http://dpdk.org/browse/dpdk/tree/drivers/net/mlx4 > > It benefits of the kernel's capabilities while the userland manages only > the IOs. > > There were some tentative to get it for other (older) drivers, named > 'bifurcated drivers', but it is stalled. > And in our testing the mlx4 driver performance is terrible. That maybe because of the overhead of infiniband library.
