[libvirt] [RFC] [PATCH 3/3 v2] vepa+vsi: Some experimental code for 802.1Qbh

[Stefan Berger]

On Sun, 2010-05-23 at 10:37 -0700, Scott Feldman wrote:
> On 5/23/10 6:41 AM, "Dave Allan" <dallan at redhat.com> wrote:
> 
> > On Sat, May 22, 2010 at 06:47:19PM -0700, Scott Feldman wrote:
> >> On 5/22/10 6:24 PM, "Dave Allan" <dallan at redhat.com> wrote:
> >> 

> > It's not impossible to do what you're suggesting here, but what's the
> > benefit?  Is it a problem to poll for even 10 or 20 seconds?
> 
> I'm worried about scaling if each poll cycle is 10-20 secs.  It's very easy
> to have 100+ virtual NICs connected to 100+ virtual ports.  In fact, I can
> create that setup today.  Would libvirt serialize the polling, polling one
> virtual port and then the next?  If not, then my scaling concern isn't
> valid.

I think polling in short intervals of 1/8 second should be ok; maybe
with some backoff if nothing happens for 2 seconds or so.

There is serialization occurring, but it's not the macvtap (setup) code
itself that does the serialization but the code is invoked as part of
building the command line for qemu which in turn is called with the
qemu_driver lock being held and thus will be serialized due to
serialization requirements of other parts.

   Stefan