[ovs-discuss] Datpath in openVswitch

[Ben Pfaff]

On Wed, Nov 20, 2013 at 10:40:31AM +0000, Vivek Kumar (EPG) wrote:
> 1) could you please confirm in OpenVswitch data flow to be @ kernel level or user level.

What's a data flow?

> 2) As some document says that When the first packet of a flow comes to
> the datapath, the datapath transmit it to the userspace using
> netlink. Does the datapath buffer the packet? Or it is just buffered
> in userspace?

The datapath does not buffer.

> 3) Will this (first)packet traversing from kernel to user space and
> user space to kernel space affect the performance.

Yes.

> 4) It seems that datapath flow entry is 5 seconds time-out, then how
> soon is the facet time_out? Where can I find the code of time_out? Or
> can we change time out value.

The maximum timeout is 5 seconds.  ofproto-dpif.c.  Modify the code.