[ovs-dev] [PATCH v11 1/3] netdev: Add optional qfill output parameter to rxq_recv()

[Jan Scheurich]

> -----Original Message-----
> From: Ben Pfaff [mailto:blp at ovn.org]
> Sent: Thursday, 12 April, 2018 18:37
> 
> On Thu, Apr 12, 2018 at 05:32:11PM +0200, Jan Scheurich wrote:
> > If the caller provides a non-NULL qfill pointer and the netdev
> > implemementation supports reading the rx queue fill level, the rxq_recv()
> > function returns the remaining number of packets in the rx queue after
> > reception of the packet burst to the caller. If the implementation does
> > not support this, it returns -ENOTSUP instead. Reading the remaining queue
> > fill level should not substantilly slow down the recv() operation.
> >
> > A first implementation is provided for ethernet and vhostuser DPDK ports
> > in netdev-dpdk.c.
> >
> > This output parameter will be used in the upcoming commit for PMD
> > performance metrics to supervise the rx queue fill level for DPDK
> > vhostuser ports.
> 
> Thanks for working on the generic netdev layer.
> 
> I wasn't sure what a qfill was, so I looked at the comment on the
> function that returned it and it says that it is a "queue fill level".
> I can kind of guess what that is, but maybe it should be spelled out a
> little more.  For example, is it the number of packets currently waiting
> to be received?  (Maybe it is the number of bytes, who knows.)  So, I
> suggest making the comment just a little more explicit.

Sure, will do that.