Rick> Which rev of netperf are you using, and areyou using the Rick> "confidence intervals" options (-i, -I)? for a long time, Rick> the linux-unique behaviour of returning the overhead bytes Rick> for SO_[SND|RCV]BUF and them being 2X what one gives in Rick> setsockopt() gave netperf some trouble - the socket buffer Rick> would double in size each iteration on a confidence interval Rick> run. Later netperf versions (late 2.3, and 2.4.X) have a Rick> kludge for this.
I believe it's netperf 2.2. I'm not using any confidence interval stuff. However, the variation is not between single runs of netperf -- if I do 5 runs of netperf in a row, I get roughly the same number from each run. For example, I might see something like TCP STREAM TEST to 192.168.145.2 : histogram Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 3869.82 and then TCP STREAM TEST to 192.168.145.2 : histogram Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 3862.41 for two successive runs. However, if I reboot the system into the same kernel (ie everything set up exactly the same), the same invocation of netperf might give TCP STREAM TEST to 192.168.145.2 : histogram Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 4389.20 Rick> Are there large changes in service demand along with the Rick> large performance changes? Not sure. How do I have netperf report service demand? - R. _______________________________________________ openib-general mailing list openib-general@openib.org http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general