| 
 
  Most likely your dom0 CPU is saturated.. It is 
  unrealistic to expect full throughput of a 10 Gig NIC. I would be surprised if 
  even linux could keep up with a receive rate of 10 Gb/s. Did 
  you try the same experiment on native linux? In  my experiments, on a 
  4-way 2.8 Ghz Xeon, dom0 consumes ~75% of one cpu for processing receive 
  packets while the guest consume ~55% of another 
CPU. With native->native or even native->dom0, I get 9.88 
Gb/s with 21% utilization of receive side CPU.  It's a nice machine and we 
make nice NICs ;-)  So, it's not unrealistic. 
  It is  expected that your dual CPU system 
  saturates at a rate slighlty above 1 Ghz. (You are also consuming extra cycles 
  to drop packets) You could confirm that the CPU is 
  saturating by running xentop while running your 
  experiments. You could avoid dropping packets and get 
  a more realistic experiment by running a TCP experiment as Ian 
  suggested i have a pending note on that, TCP test is actually 
what I tried first, and the perf was terrible due to the same packet loss.  
more info to come. -reese   |