On Sun, Jan 23, 2011 at 12:39:02PM +0200, Michael S. Tsirkin wrote: > On Sun, Jan 23, 2011 at 05:38:49PM +1100, Simon Horman wrote: > > 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: [snip] > > > > > 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. > > Yes but I think that you want to put some controlled load on host. > Let's assume that we impove the speed somehow and now you can push more > bytes per second without loss. Result might be a regression in your > test because you let the guest push "as much as it can" and suddenly it > can push more data through. OTOH with packet loss the load on host is > anywhere in between send and receive throughput: there's no easy way to > measure it from netperf: the earlier some buffers overrun, the earlier > the packets get dropped and the less the load on host. > > This is why I say that to get a specific > load on host you want to limit the sender > to a specific BW and then either > - make sure packet loss % is close to 0. > - make sure packet loss % is close to 100%. Thanks, and sorry for being a bit slow. I now see what you have been getting at with regards to limiting the tests. I will see about getting some numbers based on your suggestions. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
