[ovs-dev] Flow Control and Port Mirroring Revisited

[Simon Horman]

On Sat, Jan 22, 2011 at 11:57:42PM +0200, Michael S. Tsirkin wrote:
> On Sat, Jan 22, 2011 at 10:11:52AM +1100, Simon Horman wrote:
> > On Fri, Jan 21, 2011 at 11:59:30AM +0200, Michael S. Tsirkin wrote:
> > > On Thu, Jan 20, 2011 at 05:38:33PM +0900, Simon Horman wrote:
> > > > [ Trimmed Eric from CC list as vger was complaining that it is too long ]
> > > > 
> > > > On Tue, Jan 18, 2011 at 11:41:22AM -0800, Rick Jones wrote:
> > > > > >So it won't be all that simple to implement well, and before we try,
> > > > > >I'd like to know whether there are applications that are helped
> > > > > >by it. For example, we could try to measure latency at various
> > > > > >pps and see whether the backpressure helps. netperf has -b, -w
> > > > > >flags which might help these measurements.
> > > > > 
> > > > > Those options are enabled when one adds --enable-burst to the
> > > > > pre-compilation ./configure  of netperf (one doesn't have to
> > > > > recompile netserver).  However, if one is also looking at latency
> > > > > statistics via the -j option in the top-of-trunk, or simply at the
> > > > > histogram with --enable-histogram on the ./configure and a verbosity
> > > > > level of 2 (global -v 2) then one wants the very top of trunk
> > > > > netperf from:
> > > > 
> > > > Hi,
> > > > 
> > > > I have constructed a test where I run an un-paced  UDP_STREAM test in
> > > > one guest and a paced omni rr test in another guest at the same time.
> > > 
> > > Hmm, what is this supposed to measure?  Basically each time you run an
> > > un-paced UDP_STREAM you get some random load on the network.
> > > You can't tell what it was exactly, only that it was between
> > > the send and receive throughput.
> > 
> > Rick mentioned in another email that I messed up my test parameters a bit,
> > so I will re-run the tests, incorporating his suggestions.
> > 
> > What I was attempting to measure was the effect of an unpaced UDP_STREAM
> > on the latency of more moderated traffic. Because I am interested in
> > what effect an abusive guest has on other guests and how that my be
> > mitigated.
> > 
> > Could you suggest some tests that you feel are more appropriate?
> 
> Yes. To refraze my concern in these terms, besides the malicious guest
> you have another software in host (netperf) that interferes with
> the traffic, and it cooperates with the malicious guest.
> Right?

Yes, that is the scenario in this test.

> IMO for a malicious guest you would send
> UDP packets that then get dropped by the host.
> 
> For example block netperf in host so that
> it does not consume packets from the socket.

I'm more interested in rate-limiting netperf than blocking it.
But in any case, do you mean use iptables or tc based on
classification made by net_cls?